Difference between pages "ZFS as Root Filesystem" and "LVM Install Guide"

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== Introduction ==
== Introduction ==


This tutorial will show you how to install Funtoo on ZFS (rootfs). This tutorial is meant to be an "overlay" over the [[Funtoo_Linux_Installation|Regular Funtoo Installation]]. Follow the normal installation and only use this guide for steps 2, 3, and 8.
{{fancynote|This tutorial will show you how to install Funtoo, including the rootfs, on logical volumes. This guide is meant to complement the regular [[Funtoo_Linux_Installation|Funtoo Installation Guide]]. It is recommended that you open it in another tab/window and follow along with it as we will only be documenting the steps that are different or in addition to the regular guide.}}


=== Introduction to ZFS ===
LVM (Logical Volume Management) offers a much more flexible way of managing your storage devices. Not only does it allow you to resize your volumes


Since ZFS is a new technology for Linux, it can be helpful to understand some of its benefits, particularly in comparison to BTRFS, another popular next-generation Linux filesystem:
== Live CD ==


* On Linux, the ZFS code can be updated independently of the kernel to obtain the latest fixes. btrfs is exclusive to Linux and you need to build the latest kernel sources to get the latest fixes.
Please read the [[Funtoo Linux Installation#Live CD|Live CD]] section in the regular guide. The only thing you need in addition to the [[Requirements|requirements]] it mentions is the sys-fs/lvm2 package or equivalent. If you use [http://www.sysresccd.org/ System Rescue CD], it includes the lvm2 package.


* ZFS is supported on multiple platforms. The platforms with the best support are Solaris, FreeBSD and Linux. Other platforms with varying degrees of support are NetBSD, Mac OS X and Windows. btrfs is exclusive to Linux.
== Prepare the drives and partitions ==


* ZFS has the Adaptive Replacement Cache replacement algorithm while btrfs uses the Linux kernel's Last Recently Used replacement algorithm. The former often has an overwhelmingly superior hit rate, which means fewer disk accesses.
{{fancynote|For this guide, we are assuming you are using MBR, that you have a /dev/sda1 (a boot drive) and /dev/sdb1 (a system drive), and that you are only using LVM with one drive, even though LVM supports adding multiple hard disks and partitions to a volume group. Please adapt these instructions to suit your needs.}}


* ZFS has the ZFS Intent Log and SLOG devices, which accelerates small synchronous write performance.
Preparing the hard disk for an LVM install isn't much different from a normal install except that we won't be creating a bunch of partitions as we are going to use logical volumes instead.


* ZFS handles internal fragmentation gracefully, such that you can fill it until 100%. Internal fragmentation in btrfs can make btrfs think it is full at 10%. Btrfs has no automatic rebalancing code, so it requires a manual rebalance to correct it.
Find the disk:


* ZFS has raidz, which is like RAID 5/6 (or a hypothetical RAID 7 that supports 3 parity disks), except it does not suffer from the RAID write hole issue thanks to its use of CoW and a variable stripe size. btrfs gained integrated RAID 5/6 functionality in Linux 3.9. However, its implementation uses a stripe cache that can only partially mitigate the effect of the RAID write hole.
<console>
# fdisk -l
</console>


* ZFS send/receive implementation supports incremental update when doing backups. btrfs' send/receive implementation requires sending the entire snapshot.
Verify the disk:


* ZFS supports data deduplication, which is a memory hog and only works well for specialized workloads. btrfs has no equivalent.
<console>
 
# fdisk -l /dev/sdb
* ZFS datasets have a hierarchical namespace while btrfs subvolumes have a flat namespace.
</console>
 
* ZFS has the ability to create virtual block devices called zvols in its namespace. btrfs has no equivalent and must rely on the loop device for this functionality, which is cumbersome.
 
The only area where btrfs is ahead of ZFS is in the area of small file
efficiency. btrfs supports a feature called block suballocation, which
enables it to store small files far more efficiently than ZFS. It is
possible to use another filesystem (e.g. reiserfs) on top of a ZFS zvol
to obtain similar benefits (with arguably better data integrity) when
dealing with many small files (e.g. the portage tree).
 
For a quick tour of ZFS and have a big picture of its common operations you can consult the page [[ZFS Fun]].
 
=== Disclaimers ===
 
{{fancywarning|This guide is a work in progress. Expect some quirks.}}
{{fancyimportant|'''Since ZFS was really designed for 64 bit systems, we are only recommending and supporting 64 bit platforms and installations. We will not be supporting 32 bit platforms'''!}}


== Video Tutorial ==
Zap the disk:
 
As a companion to the installation instructions below, a YouTube video tutorial is now available:
 
{{#widget:YouTube|id=SWyThdxNoP8|width=640|height=360}}
 
== Downloading the ISO (With ZFS) ==
In order for us to install Funtoo on ZFS, you will need an environment that already provides the ZFS tools. Therefore we will download a customized version of System Rescue CD with ZFS included.
 
<pre>
Name: sysresccd-4.0.1_zfs_0.6.2.iso  (545 MB)
Release Date: 2014-02-25
md5sum 01f4e6929247d54db77ab7be4d156d85
</pre>
 
 
'''[http://ftp.osuosl.org/pub/funtoo/distfiles/sysresccd/ Download System Rescue CD with ZFS]'''<br />
 
== Creating a bootable USB from ISO (From a Linux Environment) ==
After you download the iso, you can do the following steps to create a bootable USB:


<console>
<console>
Make a temporary directory
# sgdisk --zap-all /dev/sdb
# ##i##mkdir /tmp/loop
 
Mount the iso
# ##i##mount -o ro,loop /root/sysresccd-4.0.1_zfs_0.6.2.iso /tmp/loop
 
Run the usb installer
# ##i##/tmp/loop/usb_inst.sh
</console>
</console>


That should be all you need to do to get your flash drive working.
Create the partition table:


== Booting the ISO ==
{{fancynote|If you are using MBR, review paritioning [[Funtoo_Linux_Installation#Partitioning_Using_fdisk_.28MBR.29|Partitioning Using fdisk]] and if you are using GPT, review [[Partitioning using gdisk]]. The basic idea is to create what ncessary and then allocate the rest for LVM.}}


{{fancywarning|'''When booting into the ISO, Make sure that you select the "Alternate 64 bit kernel (altker64)". The ZFS modules have been built specifically for this kernel rather than the standard kernel. If you select a different kernel, you will get a fail to load module stack error message.'''}}
For MBR, this is the boot partition (if you want it on the system drive), every else goes to LVM like so:
 
== Creating partitions ==
There are two ways to partition your disk: You can use your entire drive and let ZFS automatically partition it for you, or you can do it manually.
 
We will be showing you how to partition it '''manually''' because if you partition it manually you get to create your own layout, you get to have your own separate /boot partition (Which is nice since not every bootloader supports booting from ZFS pools), and you get to boot into RAID10, RAID5 (RAIDZ) pools and any other layouts due to you having a separate /boot partition.
 
==== gdisk (GPT Style) ====
 
'''A Fresh Start''':
 
First lets make sure that the disk is completely wiped from any previous disk labels and partitions.
We will also assume that <tt>/dev/sda</tt> is the target drive.<br />


<console>
<console>
# ##i##sgdisk -Z /dev/sda
# fdisk /dev/sdb
</console>
</console>


{{fancywarning|This is a destructive operation and the program will not ask you for confirmation! Make sure you really don't want anything on this disk.}}
<pre>
Disk /dev/sdb: 596.2 GiB, 640135028736 bytes, 1250263728 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0xaa6abfe1


Now that we have a clean drive, we will create the new layout.
Device    Boot    Start        End    Blocks  Id System
/dev/sdb1          2048    264191    131072  83 Linux
/dev/sdb2        264192 1250263727 624999768  83 Linux
</pre>


First open up the application:
For GPT, this is the BIOS boot partion and the boot partition (if you want them on the system drive), every else goes to LVM like so:


<console>
<console>
# ##i##gdisk /dev/sda
# gdisk /dev/sdb
</console>
</console>


'''Create Partition 1''' (boot):
<pre>
<console>
Disk /dev/sdb: 596.2 GiB, 640135028736 bytes, 1250263728 sectors
Command: ##i##n ↵
Units: sectors of 1 * 512 = 512 bytes
Partition Number: ##i##↵
Sector size (logical/physical): 512 bytes / 512 bytes
First sector: ##i##↵
I/O size (minimum/optimal): 512 bytes / 512 bytes
Last sector: ##i##+250M ↵
Disklabel type: dos
Hex Code: ##i##↵
Disk identifier: 0x6ba8799c
</console>


'''Create Partition 2''' (BIOS Boot Partition):
Device    Boot    Start        End    Blocks  Id System
<console>Command: ##i##n ↵
/dev/sdb1          2048      6143      2048  ef EFI (FAT-12/16/32)
Partition Number: ##i##↵
/dev/sdb2          6144    268287    131072  83 Linux
First sector: ##i##↵
/dev/sdb3        268288 1250263727 624997720  83 Linux
Last sector: ##i##+32M ↵
</pre>
Hex Code: ##i##EF02 ↵
</console>
 
'''Create Partition 3''' (ZFS):
<console>Command: ##i##n ↵
Partition Number: ##i##↵
First sector: ##i##↵
Last sector: ##i##↵
Hex Code: ##i##bf00 ↵


Command: ##i##p ↵
You'll notice in both cases that a swap partition wasn't created. This is becasue if one is desired, it can be done in LVM.


Number  Start (sector)    End (sector)  Size      Code  Name
Create the physical volume:
  1            2048          514047  250.0 MiB  8300  Linux filesystem
  2          514048          579583  32.0 MiB    EF02  BIOS boot partition
  3          579584      1953525134  931.2 GiB  BF00  Solaris root


Command: ##i##w ↵
{{fancynote|As a remindiner, for this guide, we are assuming you are using MBR, that you have a /dev/sda1 (a boot drive) and /dev/sdb1 (a system drive), and that you are only using LVM with one drive. Change this to suit your purposes.}}
</console>


 
Our first step is to create a physical volume which basically just tells the lvm where to write the data to.
=== Format your /boot partition ===


<console>
<console>
# ##i##mkfs.ext2 -m 1 /dev/sda1
# pvcreate -f -f /dev/sdb1
</console>
</console>


=== Encryption (Optional) ===
<pre>
If you want encryption, then create your encrypted vault(s) now by doing the following:
  Physical volume "/dev/sdb1" successfully created
</pre>
 
Display the physical volume:


<console>
<console>
# ##i##cryptsetup luksFormat /dev/sda3
# pvdisplay
# ##i##cryptsetup luksOpen /dev/sda3 vault_1
</console>
</console>


{{fancywarning|On some machines, a combination of ZFS and LUKS has caused instability and system crashes.}}
<pre>
 
  "/dev/sdb1" is a new physical volume of "596.17 GiB"
=== Create the zpool ===
  --- NEW Physical volume ---
We will first create the pool. The pool will be named `tank` and the disk will be aligned to 4096 (using ashift=12)
  PV Name              /dev/sdb1
<console># ##i##zpool create -f -o ashift=12 -o cachefile= -O compression=on -m none -R /mnt/funtoo tank /dev/sda3</console>
  VG Name             
 
  PV Size              596.17 GiB
{{fancyimportant|If you are using encrypted root, change '''/dev/sda3 to /dev/mapper/vault_1'''.}}
  Allocatable          NO
  PE Size              0 
  Total PE              0
  Free PE              0
  Allocated PE          0
  PV UUID              IDDrWr-t3PD-7t31-fRQ3-pay2-eMGy-1NgrD0
</pre>


{{fancynote| If you have a previous pool that you would like to import, you can do a: '''zpool import -f -R /mnt/funtoo <pool_name>'''.}}
Create the volume group:


=== Create the zfs datasets ===
Now that we have a place to store our data we need to create a volume group for it. A volume group is simply a named group of at least one physical volume. This allows multiple physical volumes to be used to store data. In our simple example we only have one physical volume so we'll create a volume group and add our physical volume to it in one command. We are going to call our volume group "funtoo" but you can name it anything you want.  
We will now create some datasets. For this installation, we will create a small but future proof amount of datasets. We will have a dataset for the OS (/), and your swap. We will also show you how to create some optional datasets: <tt>/home</tt>, <tt>/var</tt>, <tt>/usr/src</tt>, and <tt>/usr/portage</tt>.


<console>
<console>
Create some empty containers for organization purposes, and make the dataset that will hold /
# vgcreate funtoo /dev/sdb1
# ##i##zfs create -p tank/funtoo
# ##i##zfs create -o mountpoint=/ tank/funtoo/root
 
Optional, but recommended datasets: /home
# ##i##zfs create -o mountpoint=/home tank/funtoo/home
 
Optional datasets: /usr/src, /usr/portage/{distfiles,packages}
# ##i##zfs create -o mountpoint=/usr/src tank/funtoo/src
# ##i##zfs create -o mountpoint=/usr/portage -o compression=off tank/funtoo/portage
# ##i##zfs create -o mountpoint=/usr/portage/distfiles tank/funtoo/portage/distfiles
# ##i##zfs create -o mountpoint=/usr/portage/packages tank/funtoo/portage/packages
</console>
</console>


=== Create your swap zvol ===
<pre>
For modern machines that have greater than 4 GB of RAM, A swap size of 2G should be enough. However if your machine doesn't have a lot of RAM, the rule of thumb is either 2x the RAM or RAM + 1 GB.
  Volume group "funtoo" successfully created
</pre>


For this tutorial we will assume that it is a newer machine and make a 2 GB swap.
Display the volume group:


<console>
<console>
# ##i##zfs create -o sync=always -o primarycache=metadata -o secondarycache=none -o volblocksize=4K -V 2G tank/swap
# vgdisplay
</console>
</console>


=== Format your swap zvol ===
<pre>
<console>
  --- Volume group ---
# ##i##mkswap -f /dev/zvol/tank/swap
  VG Name              funtoo
# ##i##swapon /dev/zvol/tank/swap
  System ID           
</console>
  Format                lvm2
  Metadata Areas        1
  Metadata Sequence No  1
  VG Access            read/write
  VG Status            resizable
  MAX LV                0
  Cur LV                0
  Open LV              0
  Max PV                0
  Cur PV                1
  Act PV                1
  VG Size              596.17 GiB
  PE Size              4.00 MiB
  Total PE              152619
  Alloc PE / Size      0 / 0 
  Free  PE / Size      152619 / 596.17 GiB
  VG UUID              jFubWA-SGaa-w3C7-Zrst-9Hqo-mWPZ-9JqYZ4
</pre>


Now we will continue to install funtoo.
Create the logical volumes:


== Installing Funtoo ==
We now come to the heart of using LVM, logical volumes. Here we get to create logical volumes to store our data. Remember that the best part of LVM is the ability to resize volumes later on the fly so keep that in mind when deciding how big to make volumes. No need to allocate all your space right away. Also keep in mind when choosing a file system type that it must support resizing in order to take advantage of LVM's resizing features.


=== Pre-Chroot ===
For our simple example we are only going to create 4 logical volumes and use them for: (SWAP) /(ROOT), /home/my and /home/my/media.


<console>
<console>
Go into the directory that you will chroot into
# lvcreate -L 32G -n SWAP funtoo
# ##i##cd /mnt/funtoo
 
Make a boot folder and mount your boot drive
# ##i##mkdir boot
# ##i##mount /dev/sda1 boot
</console>
</console>


[[Funtoo_Linux_Installation|Now download and extract the Funtoo stage3 ...]]
<pre>
 
  Logical volume "SWAP" created
Once you've extracted the stage3, do a few more preparations and chroot into your new funtoo environment:
</pre>


<console>
<console>
Bind the kernel related directories
# lvcreate -L 64G -n ROOT funtoo
# ##i##mount -t proc none proc
# ##i##mount --rbind /dev dev
# ##i##mount --rbind /sys sys
 
Copy network settings
# ##i##cp -f /etc/resolv.conf etc
 
Make the zfs folder in 'etc' and copy your zpool.cache
# ##i##mkdir etc/zfs
# ##i##cp /etc/zfs/zpool.cache etc/zfs
 
Chroot into Funtoo
# ##i##env -i HOME=/root TERM=$TERM chroot . bash -l
</console>
</console>


=== In Chroot ===
<pre>
  Logical volume "ROOT" created
</pre>


<console>
<console>
Create a symbolic link to your mountpoints
# lvcreate -L 128G -n home_my funtoo
# ##i##ln -sf /proc/mounts /etc/mtab
 
Sync your tree
# ##i##emerge --sync
</console>
</console>
=== Add filesystems to /etc/fstab ===
Before we continue to compile and or install our kernel in the next step, we will edit the <tt>/etc/fstab</tt> file because if we decide to install our kernel through portage, portage will need to know where our <tt>/boot</tt> is, so that it can place the files in there.
Edit <tt>/etc/fstab</tt>:


<pre>
<pre>
# <fs>                  <mountpoint>    <type>          <opts>          <dump/pass>
  Logical volume "home_my" created
 
/dev/sda1              /boot          ext2            defaults        0 2
/dev/zvol/tank/swap    none            swap            sw              0 0
</pre>
</pre>
== Kernel Configuration ==
To speed up this step, you can install a pre-configured/compiled kernel called '''bliss-kernel'''. This kernel already has the correct configurations for ZFS and a variety of other scenarios. It's a vanilla kernel from kernel.org without any external patches.
To install {{Package|sys-kernel/bliss-kernel}} type the following:


<console>
<console>
# ##i##emerge bliss-kernel
# lvcreate -L 256G -n home_my_media funtoo
</console>
</console>


Now make sure that your <tt>/usr/src/linux symlink</tt> is pointing to this kernel by typing the following:
<pre>
  Logical volume "home_my_media" created
</pre>
 
Display the logical volumes:


<console>
<console>
# ##i##eselect kernel list
# lvdisplay
Available kernel symlink targets:
[1]  linux-3.12.13-KS.02 *
</console>
</console>


You should see a star next to the version you installed. In this case it was 3.12.13-KS.02. If it's not set, you can type '''eselect kernel set #'''.
<pre>
  --- Logical volume ---
  LV Path                /dev/funtoo/SWAP
  LV Name                SWAP
  VG Name                funtoo
  LV UUID                VkdEAk-Jshp-qcQ0-jU7m-m7f4-fyG6-1FZJlh
  LV Write Access        read/write
  LV Creation host, time funtoo, 2014-07-24 04:39:19 -0400
  LV Status              available
  # open                0
  LV Size                32.00 GiB
  Current LE            8192
  Segments              1
  Allocation            inherit
  Read ahead sectors    auto
  - currently set to     256
  Block device          253:1
 
  --- Logical volume ---
  LV Path                /dev/funtoo/ROOT
  LV Name                ROOT
  VG Name                funtoo
  LV UUID                2WE7dL-R5BN-dM78-eMx5-hwS8-SjWJ-mUjzL4
  LV Write Access        read/write
  LV Creation host, time funtoo, 2014-07-24 04:39:24 -0400
  LV Status              available
  # open                0
  LV Size                64.00 GiB
  Current LE            16384
  Segments              1
  Allocation            inherit
  Read ahead sectors    auto
  - currently set to    256
  Block device          253:2
 
  --- Logical volume ---
  LV Path                /dev/funtoo/home_my
  LV Name                home_my
  VG Name                funtoo
  LV UUID                OJnpYM-399Y-8pa3-iMTY-Nle3-IyK1-keDtng
  LV Write Access        read/write
  LV Creation host, time funtoo, 2014-07-24 04:40:16 -0400
  LV Status              available
  # open                0
  LV Size                128.00 GiB
  Current LE            32768
  Segments              1
  Allocation            inherit
  Read ahead sectors    auto
  - currently set to    256
  Block device          253:3
 
  --- Logical volume ---
  LV Path                /dev/funtoo/home_my_media
  LV Name                home_my_media
  VG Name                funtoo
  LV UUID                tt7cin-igC4-VD85-fDKV-J692-fV3F-auJYcU
  LV Write Access        read/write
  LV Creation host, time funtoo, 2014-07-24 04:40:30 -0400
  LV Status              available
  # open                0
  LV Size                256.00 GiB
  Current LE            65536
  Segments              1
  Allocation            inherit
  Read ahead sectors    auto
  - currently set to    256
  Block device          253:4
</pre>


== Installing the ZFS userspace tools and kernel modules ==
Activate swap:
Emerge {{Package|sys-fs/zfs}}. This package will bring in {{Package|sys-kernel/spl}}, and {{Package|sys-fs/zfs-kmod}} as its dependencies:


<console>
<console>
# ##i##emerge zfs
# mkswap /dev/mapper/funtoo-SWAP
</console>
</console>


Check to make sure that the zfs tools are working. The <code>zpool.cache</code> file that you copied before should be displayed.
<pre>
Setting up swapspace version 1, size = 33554428 KiB
no label, UUID=ccc83857-28da-4508-a393-84e974e0eeb1
</pre>


<console>
<console>
# ##i##zpool status
# swapon /dev/mapper/funtoo-SWAP
# ##i##zfs list
</console>
</console>


If everything worked, continue.
Create the filesystems:


== Create the initramfs ==
{{fancynote|Before proceeding you should read through the brief section [[Funtoo Linux Installation#Creating filesystems|Creating filesystems]] in the install guide and decide what type of filesystem you would like to use. Do not actually create any file systems though, we will cover that below.}}
There are two ways to do this, you can use "genkernel" or "bliss-initramfs". Both will be shown.


=== genkernel ===
Install genkernel and run it:
<console>
<console>
# ##i##emerge genkernel
# mkfs.ext2      /dev/sda1
 
You only need to add --luks if you used encryption
# ##i##genkernel --zfs --luks initramfs
</console>
</console>


=== Bliss Initramfs Creator ===
<pre>
If you are encrypting your drives, then add the "luks" use flag to your package.use before emerging:
[...]
</pre>


<console>
<console>
# ##i##echo "sys-kernel/bliss-initramfs luks" >> /etc/portage/package.use
# mkfs.ext4      /dev/mapper/funtoo-ROOT
</console>
</console>


Now install the program and run it:
<pre>
<console>
mke2fs 1.42.10 (18-May-2014)
# ##i##emerge bliss-initramfs
Creating filesystem with 16777216 4k blocks and 4194304 inodes
Filesystem UUID: 0ab8f9ab-e824-4d69-a9c4-201d4ccd99ac
Superblock backups stored on blocks:  
32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
4096000, 7962624, 11239424


You can either run it without any parameters to get an interactive menu
Allocating group tables: done                           
or you can pass the parameters directly. 1 = zfs, 6 = encrypted zfs, and the kernel name.
Writing inode tables: done                           
# ##i##bliss-initramfs 1 3.12.13-KS.02
Creating journal (32768 blocks): done
</console>
Writing superblocks and filesystem accounting information: done 
</pre>


=== Moving into the correct location ===
Place the file that was generated by the above applications into either your /boot folder (If you are using boot-update) or into your /boot/kernels/3.12.13-KS.02 folder (If you are using bliss-boot). For bliss-boot, the file needs to be called 'initrd' rather than 'initrd-3.12.13-KS.02'.
==== boot-update ====
<console>
<console>
# ##i##mv initrd-3.12.13-KS.02 /boot
# mkfs.ext4      /dev/mapper/funtoo-home_my
</console>
</console>


==== bliss-boot ====
<pre>
<console>
mke2fs 1.42.10 (18-May-2014)
# ##i##mv initrd-3.12.13-KS.02 /boot/kernels/3.12.13-KS.02/initrd
Creating filesystem with 33554432 4k blocks and 8388608 inodes
</console>
Filesystem UUID: 46e394c1-3635-4f13-ba51-10c537d2b5ed
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
4096000, 7962624, 11239424, 20480000, 23887872


== Installing & Configuring the Bootloader ==
Allocating group tables: done                           
Writing inode tables: done                           
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done   
</pre>


=== GRUB 2 (Optional if you are using another bootloader) ===
<console>
<console>
# ##i##emerge grub
# mkfs.xfs        /dev/mapper/funtoo-home_my_media
</console>
</console>


You can check that grub is version 2.00 by typing the following command:
<pre>
meta-data=/dev/mapper/funtoo-home_my_media isize=256    agcount=4, agsize=16777216 blks
        =                      sectsz=512  attr=2, projid32bit=0
data    =                      bsize=4096  blocks=67108864, imaxpct=25
        =                      sunit=0      swidth=0 blks
naming  =version 2              bsize=4096  ascii-ci=0
log      =internal log          bsize=4096  blocks=32768, version=2
        =                      sectsz=512  sunit=0 blks, lazy-count=1
realtime =none                  extsz=4096  blocks=0, rtextents=0
</pre>
 
Label the filesystems:


<console>
<console>
# ##i##grub-install --version
# e2label /dev/sda1 boot
grub-install (GRUB) 2.00
</console>
</console>


Now install grub to the drive itself (not a partition):
== Prepare for chroot ==
<console>
# ##i##grub-install /dev/sda
</console>


You should receive the following message:
Activiate the volumes:


<console>
<console>
Installation finished. No error reported.
# vgscan
# vgchange -a y
</console>
</console>


You should now see some a grub directory with some files inside your /boot folder:
Mount the filesystems:


<console>
<console>
# ##i##ls -l /boot/grub
# mkdir -p /mnt/funtoo
total 2520
# mount /dev/mapper/funtoo-ROOT /mnt/funtoo
-rw-r--r-- 1 root root    1024 Jan  4 16:09 grubenv
# mkdir -p /mnt/funtoo/boot
drwxr-xr-x 2 root root    8192 Jan 12 14:29 i386-pc
# mount /dev/sda1 /mnt/funtoo/boot
drwxr-xr-x 2 root root    4096 Jan 12 14:28 locale
# mkdir -p /mnt/funtoo/home/my
-rw-r--r-- 1 root root 2555597 Feb  4 11:50 unifont.pf2
# mount /dev/mapper/funtoo-home_my /mnt/funtoo/home/my
# mkdir -p /mnt/funtoo/home/my/media
# mount /dev/mapper/funtoo-home_my_media /mnt/funtoo/home/my/media
</console>
</console>


=== Extlinux (Optional if you are using another bootloader) ===
Install the bootloader:
To install extlinux, you can follow the guide here: [[Extlinux|Link to Extlinux Guide]].
 
=== LILO (Optional if you are using another bootloader) ===
To install lilo you can type the following:


<console>
<console>
# ##i##emerge lilo
# grub-install /dev/sda1
</console>
</console>


=== boot-update ===
== Resume from Funtoo Linux Installation ==
boot-update comes as a dependency of grub2, so if you already installed grub, it's already on your system!
 
You may safely resume from [http://www.funtoo.org/Funtoo_Linux_Installation#Installing_the_Stage_3_tarball Installing the Stage 3 tarball] with few exceptions:


==== Genkernel ====
=== fstab ===
If your using genkernel you must add 'real_root=ZFS=<root>' and 'dozfs' to your params.
Example entry for <tt>/etc/boot.conf</tt>:


<pre>
<pre>
"Funtoo ZFS" {
# <filesystem>                  <mountpoint>        <type>      <opts>      <dump>      <pass>
        kernel vmlinuz[-v]
/dev/funtoo/SWAP                none                swap        sw          0          0
        initrd initramfs-genkernel-x86_64[-v]
/dev/funtoo/ROOT                /                  ext4        noatime    0          1
        params real_root=ZFS=tank/funtoo/root
LABEL=boot                      /boot              ext2        noatime    0          0
        params += dozfs=force
/dev/funtoo/home_my            /home/my            ext4        noatime    0          2
        # Also add 'params += crypt_root=/dev/sda3' if you used encryption
/dev/funtoo/home_my_media      /home/my/media      xfs         noatime    0          2
         # Adjust the above setting to your system if needed
}
</pre>
</pre>


==== Bliss Initramfs Creator ====
=== kernel ===
If you used Bliss Initramfs Creator then all you need to do is add 'root=<root>' to your params.
Example entry for <tt>/etc/boot.conf</tt>:


<pre>
Enable kernel options:
"Funtoo ZFS" {
{{kernelop
        kernel vmlinuz[-v]
|title=
        initrd initrd[-v]
|desc=
        params root=tank/funtoo/root quiet
General setup --->
        # If you have an encrypted device with a regular passphrase,
      [*] Initial RAM filesystem and RAM disk (initramfs/initrd) support
        # you can add the following line
}}
        params += enc_root=/dev/sda3 enc_type=pass
{{kernelop
}
|title=
</pre>
|desc=
 
Device Drivers --->
After editing /etc/boot.conf, you just need to run boot-update to update grub.cfg
      Generic Driver Options --->
      [*] Maintain a devtmpfs filesystem to mount at /dev
}}
{{kernelop
|title=
|desc=
Device Drivers --->
      [*] Multiple devices driver support --->
      <*>Device Mapper Support
}}


<console>
Build initramfs (genkernel):
###i## boot-update
</console>


=== bliss-boot ===
{{fancynote|This builds only an initramfs with lvm support. It does not build the whole kernel so you still have to do that.}}
This is a new program that is designed to generate a simple, human-readable/editable, configuration file for a variety of bootloaders. It currently supports grub2, extlinux, and lilo.


You can install it via the following command:
<console>
<console>
# ##i##emerge bliss-boot
# genkernel --lvm initramfs
</console>
</console>


==== Bootloader Configuration ====
=== boot-update ===
In order to generate our bootloader configuration file, we will first configure bliss-boot so that it knows what we want. The 'bliss-boot' configuration file is located in '''/etc/bliss-boot/conf.py'''. Open that file and make sure that the following variables are set appropriately:


<pre>
<pre>
# This should be set to the bootloader you installed earlier: (grub2, extlinux, and lilo are the available options)
boot {
bootloader = "grub2"
  generate grub
  default "Funtoo Linux"
  timeout 3
}


# This should be set to the kernel you installed earlier
"Funtoo Linux" {
default = "3.12.13-KS.02"
  kernel kernel-genkernel-x86_64-3.14.13
</pre>
  initrd initramfs-genkernel-x86_64-3.14.13
 
  params += dolvm real_root=/dev/mapper/funtoo-ROOT rootfstype=ext4 resume=swap:/dev/mapper/funtoo-SWAP quiet
Scroll all the way down until you find 'kernels'. You will need to add the kernels and the options
you want for these kernels here. Below are a few configuration options depending if you are using
'''bliss-initramfs''' or '''genkernel'''.
 
===== Genkernel =====
 
<pre>
kernel = {
    '3.12.13-KS.02' : 'real_root=ZFS=tank/funtoo/root dozfs=force quiet',
}
}
</pre>
</pre>


'''If you are using encryption you can add the crypt_root option:'''
=== software ===


<pre>
<console>
kernel = {
# emerge -va lvm2
    '3.12.13-KS.02' : 'real_root=ZFS=tank/funtoo/root dozfs=force crypt_root=/dev/sda3 quiet',
</console>
}
</pre>


===== Bliss Initramfs Creator =====
For the most part, LVM "just works" without any additional configuration. This is especially true for versions below 2.02.107. If you are using >=sys-fs/lvm2-2.02.107 with Funtoo, there are two features be desired that are turned off by default:
<pre>
kernel = {
    '3.12.13-KS.02' : 'root=tank/funtoo/root quiet',
}
</pre>


'''If you are using encryption then you would let the initramfs know:'''
The Metadata Daemon ([https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Logical_Volume_Manager_Administration/metadatadaemon.html lvmetad])


#"What type of encryption authentication you want to use? ('''enc_type=''')
Thinly-Provisioned Logical Volumes ([https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Logical_Volume_Manager_Administration/thinprovisioned_volumes.html Thin Volumes])
::* pass = will ask for passphrase directly
::* key = a plain unencrypted key file
::* key_gpg = an encrypted key file
#"Where is the encrypted drive?" ('''enc_root=''')
#"Where is the root pool after it has been decrypted?" ('''root=''')


<pre>
Enabling either is simply a matter of enabling their USE flags.
kernel = {
    '3.12.13-KS.02' : 'root=tank/funtoo/root enc_root=/dev/sda3 enc_type=pass quiet',
}
</pre>


==== Generate the configuration ====
== Cleaning up ==
Now that we have configure our '''/etc/bliss-boot/conf.py''' file, we can generate our config. Simply run the following command:


<console>
<console>
# ##i##bliss-boot
# exit
# cd /
# cat /proc/mounts | grep funtoo | awk '{print $2}' | grep "^$MOUNTPOINT" | sort -r | xargs umount
# umount /mnt/funtoo
# swapoff -v /dev/mapper/funtoo-SWAP
# vgchange -a n
# init 0
</console>
</console>


This will generate a configuration file for the bootloader you specified previously in your current directory. You can check your config file before hand to make sure it doesn't have any errors. Simply open either: grub.cfg, extlinux.conf, or lilo.conf.
== Special notes ==


Once you have checked it for errors, place this file in the correct directory:
=== Resizing ===


* grub2 = /boot/grub/
{{fancynote|Resizing is filesystem specific. Most can be grown but cannot be shrunk.}}
* extlinux = /boot/extlinux/
* lilo = /etc/lilo.conf


=== LILO (Optional if you are using another bootloader) ===
==== Growing /home/my by 8G ====
Now that bliss-boot generated the lilo.conf file, move that config file to its appropriate location
and install lilo to the MBR:


<console>
<console>
# ##i##mv lilo.conf /etc
# lvextend -L+8G /dev/mapper/funtoo-home_my
# ##i##lilo
</console>


You should see the following:
===== ext2/ext3/ext4 =====


Warning: LBA32 addressing assumed
<console>
Added Funtoo + *
# resize2fs /mnt/funtoo/home/my
One warning was issued
</console>
</console>


== Final configuration ==
===== xfs =====
=== Add the zfs tools to openrc ===
<console># ##i##rc-update add zfs boot</console>
 
=== Clean up and reboot ===
We are almost done, we are just going to clean up, '''set our root password''', and unmount whatever we mounted and get out.


<console>
<console>
Delete the stage3 tarball that you downloaded earlier so it doesn't take up space.
# xfs_growfs /mnt/funtoo/home/my
# ##i##cd /
# ##i##rm stage3-latest.tar.xz
 
Set your root password
# ##i##passwd
>> Enter your password, you won't see what you are writing (for security reasons), but it is there!
 
Get out of the chroot environment
# ##i##exit
 
Unmount all the kernel filesystem stuff and boot (if you have a separate /boot)
# ##i##umount -l proc dev sys boot
 
Turn off the swap
# ##i##swapoff /dev/zvol/tank/swap
 
Export the zpool
# ##i##cd /
# ##i##zpool export tank
 
Reboot
# ##i##reboot
</console>
</console>


{{fancyimportant|'''Don't forget to set your root password as stated above before exiting chroot and rebooting. If you don't set the root password, you won't be able to log into your new system.'''}}
==== Shrinking /home/my by 8G ====
 
and that should be enough to get your system to boot on ZFS.


== After reboot ==
{{fancynote|You generally need to umount first.}}


=== Forgot to reset password? ===
===== ext2/ext3/ext4 =====
==== System Rescue CD ====
If you aren't using bliss-initramfs, then you can reboot back into your sysresccd and reset through there by mounting your drive, chrooting, and then typing passwd.


Example:
<console>
<console>
# ##i##zpool import -f -R /mnt/funtoo tank
# umount /mnt/funtoo/home/my
# ##i##chroot /mnt/funtoo bash -l
# lvreduce -r -L -8G /dev/mapper/funtoo-home_my
# ##i##passwd
# ##i##exit
# ##i##zpool export -f tank
# ##i##reboot
</console>
</console>


==== Using bliss-initramfs ====
===== xfs =====
If you forgot to reset your password and are using '''bliss-initramfs''', you can add the '''su''' option to your bootloader parameters and the initramfs will throw you into the rootfs of your drive. In there you can run 'passwd' and then type 'exit'. Once you type 'exit', the initramfs will continue to boot your system as normal.


=== Create initial ZFS Snapshot ===
XFS cannot be shrunk.
Continue to set up anything you need in terms of /etc configurations. Once you have everything the way you like it, take a snapshot of your system. You will be using this snapshot to revert back to this state if anything ever happens to your system down the road. The snapshots are cheap, and almost instant.  


To take the snapshot of your system, type the following:
== Beyond the basics ==
<console># ##i##zfs snapshot -r tank@install</console>


To see if your snapshot was taken, type:
The [[LVM Fun]] page may be of interest.
<console># ##i##zfs list -t snapshot</console>


If your machine ever fails and you need to get back to this state, just type (This will only revert your / dataset while keeping the rest of your data intact):
As well as these pages from Red Hat: [https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Logical_Volume_Manager_Administration/snapshot_command.html Creating Snapshot Volumes]
<console># ##i##zfs rollback tank/funtoo/root@install</console>
[https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Logical_Volume_Manager_Administration/thinly_provisioned_volume_creation.html Creating Thinly-Provionsed Logical Volumes]
 
[https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Logical_Volume_Manager_Administration/mirror_create.html Creating Mirrored Volumes]
{{fancyimportant|'''For a detailed overview, presentation of ZFS' capabilities, as well as usage examples, please refer to the [[ZFS_Fun|ZFS Fun]] page.'''}}
 
== Troubleshooting ==
 
=== Starting from scratch ===
If your installation has gotten screwed up for whatever reason and you need a fresh restart, you can do the following from sysresccd to start fresh:
 
<console>
Destroy the pool and any snapshots and datasets it has
# ##i##zpool destroy -R -f tank
 
This deletes the files from /dev/sda1 so that even after we zap, recreating the drive in the exact sector
position and size will not give us access to the old files in this partition.
# ##i##mkfs.ext2 /dev/sda1
# ##i##sgdisk -Z /dev/sda
</console>
 
Now start the guide again :).


[[Category:HOWTO]]
[[Category:HOWTO]]
[[Category:Filesystems]]
[[Category:Featured]]
[[Category:Install]]
[[Category:Install]]
 
[[Category:Official Documentation]]
__NOTITLE__

Revision as of 11:05, July 24, 2014

Introduction

   Note

This tutorial will show you how to install Funtoo, including the rootfs, on logical volumes. This guide is meant to complement the regular Funtoo Installation Guide. It is recommended that you open it in another tab/window and follow along with it as we will only be documenting the steps that are different or in addition to the regular guide.

LVM (Logical Volume Management) offers a much more flexible way of managing your storage devices. Not only does it allow you to resize your volumes

Live CD

Please read the Live CD section in the regular guide. The only thing you need in addition to the requirements it mentions is the sys-fs/lvm2 package or equivalent. If you use System Rescue CD, it includes the lvm2 package.

Prepare the drives and partitions

   Note

For this guide, we are assuming you are using MBR, that you have a /dev/sda1 (a boot drive) and /dev/sdb1 (a system drive), and that you are only using LVM with one drive, even though LVM supports adding multiple hard disks and partitions to a volume group. Please adapt these instructions to suit your needs.

Preparing the hard disk for an LVM install isn't much different from a normal install except that we won't be creating a bunch of partitions as we are going to use logical volumes instead.

Find the disk: 

root # fdisk -l

Verify the disk: 

root # fdisk -l /dev/sdb

Zap the disk: 

root # sgdisk --zap-all /dev/sdb

Create the partition table:

   Note

If you are using MBR, review paritioning Partitioning Using fdisk and if you are using GPT, review Partitioning using gdisk. The basic idea is to create what ncessary and then allocate the rest for LVM.

For MBR, this is the boot partition (if you want it on the system drive), every else goes to LVM like so: 

root # fdisk /dev/sdb

Disk /dev/sdb: 596.2 GiB, 640135028736 bytes, 1250263728 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0xaa6abfe1

Device    Boot     Start        End    Blocks  Id System
/dev/sdb1           2048     264191    131072  83 Linux
/dev/sdb2         264192 1250263727 624999768  83 Linux

For GPT, this is the BIOS boot partion and the boot partition (if you want them on the system drive), every else goes to LVM like so: 

root # gdisk /dev/sdb

Disk /dev/sdb: 596.2 GiB, 640135028736 bytes, 1250263728 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x6ba8799c

Device    Boot     Start        End    Blocks  Id System
/dev/sdb1           2048       6143      2048  ef EFI (FAT-12/16/32)
/dev/sdb2           6144     268287    131072  83 Linux
/dev/sdb3         268288 1250263727 624997720  83 Linux

You'll notice in both cases that a swap partition wasn't created. This is becasue if one is desired, it can be done in LVM.

Create the physical volume:

   Note

As a remindiner, for this guide, we are assuming you are using MBR, that you have a /dev/sda1 (a boot drive) and /dev/sdb1 (a system drive), and that you are only using LVM with one drive. Change this to suit your purposes.

Our first step is to create a physical volume which basically just tells the lvm where to write the data to. 

root # pvcreate -f -f /dev/sdb1

  Physical volume "/dev/sdb1" successfully created

Display the physical volume: 

root # pvdisplay

  "/dev/sdb1" is a new physical volume of "596.17 GiB"
  --- NEW Physical volume ---
  PV Name               /dev/sdb1
  VG Name               
  PV Size               596.17 GiB
  Allocatable           NO
  PE Size               0   
  Total PE              0
  Free PE               0
  Allocated PE          0
  PV UUID               IDDrWr-t3PD-7t31-fRQ3-pay2-eMGy-1NgrD0

Create the volume group:

Now that we have a place to store our data we need to create a volume group for it. A volume group is simply a named group of at least one physical volume. This allows multiple physical volumes to be used to store data. In our simple example we only have one physical volume so we'll create a volume group and add our physical volume to it in one command. We are going to call our volume group "funtoo" but you can name it anything you want. 

root # vgcreate funtoo /dev/sdb1

  Volume group "funtoo" successfully created

Display the volume group: 

root # vgdisplay

  --- Volume group ---
  VG Name               funtoo
  System ID             
  Format                lvm2
  Metadata Areas        1
  Metadata Sequence No  1
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                0
  Open LV               0
  Max PV                0
  Cur PV                1
  Act PV                1
  VG Size               596.17 GiB
  PE Size               4.00 MiB
  Total PE              152619
  Alloc PE / Size       0 / 0   
  Free  PE / Size       152619 / 596.17 GiB
  VG UUID               jFubWA-SGaa-w3C7-Zrst-9Hqo-mWPZ-9JqYZ4

Create the logical volumes:

We now come to the heart of using LVM, logical volumes. Here we get to create logical volumes to store our data. Remember that the best part of LVM is the ability to resize volumes later on the fly so keep that in mind when deciding how big to make volumes. No need to allocate all your space right away. Also keep in mind when choosing a file system type that it must support resizing in order to take advantage of LVM's resizing features.

For our simple example we are only going to create 4 logical volumes and use them for: (SWAP) /(ROOT), /home/my and /home/my/media. 

root # lvcreate -L 32G -n SWAP funtoo

  Logical volume "SWAP" created

root # lvcreate -L 64G -n ROOT funtoo

  Logical volume "ROOT" created

root # lvcreate -L 128G -n home_my funtoo

  Logical volume "home_my" created

root # lvcreate -L 256G -n home_my_media funtoo

  Logical volume "home_my_media" created

Display the logical volumes: 

root # lvdisplay

  --- Logical volume ---
  LV Path                /dev/funtoo/SWAP
  LV Name                SWAP
  VG Name                funtoo
  LV UUID                VkdEAk-Jshp-qcQ0-jU7m-m7f4-fyG6-1FZJlh
  LV Write Access        read/write
  LV Creation host, time funtoo, 2014-07-24 04:39:19 -0400
  LV Status              available
  # open                 0
  LV Size                32.00 GiB
  Current LE             8192
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:1
   
  --- Logical volume ---
  LV Path                /dev/funtoo/ROOT
  LV Name                ROOT
  VG Name                funtoo
  LV UUID                2WE7dL-R5BN-dM78-eMx5-hwS8-SjWJ-mUjzL4
  LV Write Access        read/write
  LV Creation host, time funtoo, 2014-07-24 04:39:24 -0400
  LV Status              available
  # open                 0
  LV Size                64.00 GiB
  Current LE             16384
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:2
   
  --- Logical volume ---
  LV Path                /dev/funtoo/home_my
  LV Name                home_my
  VG Name                funtoo
  LV UUID                OJnpYM-399Y-8pa3-iMTY-Nle3-IyK1-keDtng
  LV Write Access        read/write
  LV Creation host, time funtoo, 2014-07-24 04:40:16 -0400
  LV Status              available
  # open                 0
  LV Size                128.00 GiB
  Current LE             32768
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:3
   
  --- Logical volume ---
  LV Path                /dev/funtoo/home_my_media
  LV Name                home_my_media
  VG Name                funtoo
  LV UUID                tt7cin-igC4-VD85-fDKV-J692-fV3F-auJYcU
  LV Write Access        read/write
  LV Creation host, time funtoo, 2014-07-24 04:40:30 -0400
  LV Status              available
  # open                 0
  LV Size                256.00 GiB
  Current LE             65536
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:4

Activate swap: 

root # mkswap /dev/mapper/funtoo-SWAP

Setting up swapspace version 1, size = 33554428 KiB
no label, UUID=ccc83857-28da-4508-a393-84e974e0eeb1

root # swapon /dev/mapper/funtoo-SWAP

Create the filesystems:

   Note

Before proceeding you should read through the brief section Creating filesystems in the install guide and decide what type of filesystem you would like to use. Do not actually create any file systems though, we will cover that below. 

root # mkfs.ext2       /dev/sda1

[...]

root # mkfs.ext4       /dev/mapper/funtoo-ROOT

mke2fs 1.42.10 (18-May-2014)
Creating filesystem with 16777216 4k blocks and 4194304 inodes
Filesystem UUID: 0ab8f9ab-e824-4d69-a9c4-201d4ccd99ac
Superblock backups stored on blocks: 
	32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, 
	4096000, 7962624, 11239424

Allocating group tables: done                            
Writing inode tables: done                            
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done   

root # mkfs.ext4       /dev/mapper/funtoo-home_my

mke2fs 1.42.10 (18-May-2014)
Creating filesystem with 33554432 4k blocks and 8388608 inodes
Filesystem UUID: 46e394c1-3635-4f13-ba51-10c537d2b5ed
Superblock backups stored on blocks: 
	32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, 
	4096000, 7962624, 11239424, 20480000, 23887872

Allocating group tables: done                            
Writing inode tables: done                            
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done     

root # mkfs.xfs        /dev/mapper/funtoo-home_my_media

meta-data=/dev/mapper/funtoo-home_my_media isize=256    agcount=4, agsize=16777216 blks
         =                       sectsz=512   attr=2, projid32bit=0
data     =                       bsize=4096   blocks=67108864, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0
log      =internal log           bsize=4096   blocks=32768, version=2
         =                       sectsz=512   sunit=0 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0

Label the filesystems: 

root # e2label /dev/sda1 boot

Prepare for chroot

Activiate the volumes: 

root # vgscan
root # vgchange -a y

Mount the filesystems: 

root # mkdir -p /mnt/funtoo
root # mount /dev/mapper/funtoo-ROOT /mnt/funtoo
root # mkdir -p /mnt/funtoo/boot
root # mount /dev/sda1 /mnt/funtoo/boot
root # mkdir -p /mnt/funtoo/home/my
root # mount /dev/mapper/funtoo-home_my /mnt/funtoo/home/my
root # mkdir -p /mnt/funtoo/home/my/media
root # mount /dev/mapper/funtoo-home_my_media /mnt/funtoo/home/my/media

Install the bootloader: 

root # grub-install /dev/sda1

Resume from Funtoo Linux Installation

You may safely resume from Installing the Stage 3 tarball with few exceptions:

fstab

# <filesystem>                  <mountpoint>        <type>      <opts>      <dump>      <pass>
/dev/funtoo/SWAP                none                swap        sw          0           0
/dev/funtoo/ROOT                /                   ext4        noatime     0           1
LABEL=boot                      /boot               ext2        noatime     0           0
/dev/funtoo/home_my             /home/my            ext4        noatime     0           2
/dev/funtoo/home_my_media       /home/my/media      xfs         noatime     0           2

kernel

Enable kernel options: 

General setup --->
      [*] Initial RAM filesystem and RAM disk (initramfs/initrd) support
Device Drivers --->
      Generic Driver Options ---> 
      [*] Maintain a devtmpfs filesystem to mount at /dev
Device Drivers --->
      [*] Multiple devices driver support --->
      <*>Device Mapper Support

Build initramfs (genkernel):

   Note

This builds only an initramfs with lvm support. It does not build the whole kernel so you still have to do that. 

root # genkernel --lvm initramfs

boot-update

boot {
  generate grub
  default "Funtoo Linux"
  timeout 3
}

"Funtoo Linux" {
  kernel kernel-genkernel-x86_64-3.14.13
  initrd initramfs-genkernel-x86_64-3.14.13
  params += dolvm real_root=/dev/mapper/funtoo-ROOT rootfstype=ext4 resume=swap:/dev/mapper/funtoo-SWAP quiet
}

software

root # emerge -va lvm2

For the most part, LVM "just works" without any additional configuration. This is especially true for versions below 2.02.107. If you are using >=sys-fs/lvm2-2.02.107 with Funtoo, there are two features be desired that are turned off by default:

The Metadata Daemon (lvmetad)

Thinly-Provisioned Logical Volumes (Thin Volumes)

Enabling either is simply a matter of enabling their USE flags.

Cleaning up

root # exit
root # cd /
root # cat /proc/mounts | grep funtoo | awk '{print $2}' | grep "^$MOUNTPOINT" | sort -r | xargs umount
root # umount /mnt/funtoo
root # swapoff -v /dev/mapper/funtoo-SWAP
root # vgchange -a n
root # init 0

Special notes

Resizing

   Note

Resizing is filesystem specific. Most can be grown but cannot be shrunk.

Growing /home/my by 8G

root # lvextend -L+8G /dev/mapper/funtoo-home_my
ext2/ext3/ext4
root # resize2fs /mnt/funtoo/home/my
xfs
root # xfs_growfs /mnt/funtoo/home/my

Shrinking /home/my by 8G

   Note

You generally need to umount first.

ext2/ext3/ext4
root # umount /mnt/funtoo/home/my
root # lvreduce -r -L -8G /dev/mapper/funtoo-home_my
xfs

XFS cannot be shrunk.

Beyond the basics

The LVM Fun page may be of interest.

As well as these pages from Red Hat: Creating Snapshot Volumes Creating Thinly-Provionsed Logical Volumes Creating Mirrored Volumes

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