Difference between pages "ZFS Install Guide" and "Installing a Cron Daemon"

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=== Disclaimers ===
 
 
* This guide will only show you how to install Funtoo/ZFS on a 64 bit system!
 
 
* This guide is also using new technologies such as bliss-boot/initramfs/kernel. If you would like to use boot-update and or genkernel, please check out the [[ZFS_Install_Guide_Addendum|ZFS Install Guide's Addendum]].
 
 
* This guide is a work in progress.
 
 
 
== Introduction ==
 
== Introduction ==
 +
Cron daemons allow you to configure certain tasks to be run at specific times. Installing a cron daemon is a good idea because some packages may assume that you have a cron daemon installed and create jobs to update their databases with a cron daemon. There are several different loggers available to Funtoo users:
 +
* '''Fcron'''
 +
* '''Cronie'''
 +
* '''Vixie-Cron'''
  
In this guide we will show you how to install Funtoo on Native ZFS. The tutorial is meant to be an "overlay" over the [[Funtoo_Linux_Installation|Regular Funtoo Installation]]. Follow the normal guide during parts that are omitted.
+
== Installation ==
 
+
To install the cron daemon, run the following command:  
=== Introduction to ZFS ===
+
 
+
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:
+
 
+
* 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.
+
 
+
* 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.
+
 
+
* 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.
+
 
+
* ZFS has the ZFS Intent Log and SLOG devices, which accelerates small synchronous write performance.
+
 
+
* 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.
+
 
+
* 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.
+
 
+
* ZFS send/receive implementation supports incremental update when doing backups. btrfs' send/receive implementation requires sending the entire snapshot.
+
 
+
* ZFS supports data deduplication, which is a memory hog and only works well for specialized workloads. btrfs has no equivalent.
+
 
+
* ZFS datasets have a hierarchical namespace while btrfs subvolumes have a flat namespace.
+
 
+
* 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]].
+
 
+
 
+
== Video Tutorial ==
+
 
+
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) ==
+
Now we will download the iso, plug in our flash drive, and install sysresccd into the drive using the default sysresccd install script:
+
 
+
 
<console>
 
<console>
Download the iso to your home directory
+
# ##i## emerge --ask fcron
# ##i##cd ~/
+
# ##i##[Download ISO]
+
  
Make a temporary directory to mount loop the iso
+
These are the packages that would be merged, in order:
# ##i##mkdir /tmp/loop
+
  
Mount the iso
+
Calculating dependencies... done!
# ##i##mount -o ro,loop ~/sysresccd-4.0.1_zfs_0.6.2.iso /tmp/loop
+
[ebuild  N    ] sys-process/cronbase-0.3.2-r1
 +
[ebuild  N    ] sys-process/fcron-3.1.2-r2  USE="mta pam readline system-crontab -debug (-selinux)" LINGUAS="-fr"
  
Run the usb installer
+
Would you like to merge these packages? [Yes/No]##i## yes
# ##i##/tmp/loop/usb_inst.sh
+
 
</console>
 
</console>
  
That should be all you need to do to get your flash drive working.
+
Now enable the cron init script so that is starts when your system boots, and enable the cron daemon:
 
+
{{fancywarning|Make sure the USB you want to use is unmounted before running the script, or it will fail. The script will partition, and mount your usb to /mnt/backup automatically.}}
+
 
+
== Booting the ISO ==
+
 
+
{{fancywarning|Select the "Alternate 64 bit kernel (altker64)" option in the System Rescue CD Boot Menu. 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.}}
+
 
+
== Creating partitions ==
+
There are two ways to partition your disk: You can use your entire drive and let ZFS automatically partition it, or you can do it manually.
+
 
+
We will be showing you how to partition it '''manually''' because if you do so, 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 without any hassles 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
+
# ##i##rc-update add fcron default
 +
* service fcron added to runlevel default
 +
# ##i##rc
 +
* Caching service dependencies ...              [ ok ]
 +
* Starting fcron ...                            [ ok ]
 
</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.}}
+
=== System Cron Jobs ===
  
Now that we have a clean drive, we will create the new layout.
+
After the cron daemon has been emerged, you may see a message to run <tt>emerge --config</tt> to configure your cron daemon to process system cron jobs. System cron jobs are scripts that are installed by various packages into the following directories:
  
First open up the application:
+
* <tt>/etc/cron.hourly</tt>
 +
* <tt>/etc/cron.daily</tt>
 +
* <tt>/etc/cron.weekly</tt>
 +
* <tt>/etc/cron.monthly</tt>
  
<console>
+
For example, you should find a <tt>/etc/cron.daily/man-db</tt> script that is installed by the <tt>man-db</tt> ebuild. This system cron job's purpose is to update the man cache every day, and it will run only if you enable your cron daemon to manage system cron jobs.
# ##i##gdisk /dev/sda
+
</console>
+
  
'''Create Partition 1''' (boot):
+
You may choose to enable your cron daemon so that it runs system cron jobs, or choose not to. Enabling a cron daemon to run system cron jobs will result in a bit more disk and CPU activity on your system, but should ensure that the system runs more optimally most of the time (proper caching of man pages, etc.) It is recommended for most systems, but your system will still function without system cron jobs active.
<console>
+
Command: ##i##n ↵
+
Partition Number: ##i##↵
+
First sector: ##i##↵
+
Last sector: ##i##+250M ↵
+
Hex Code: ##i##↵
+
</console>
+
  
'''Create Partition 2''' (BIOS Boot Partition):
+
If you would like to have your system run system cron jobs, use <tt>emerge --config</tt> as specified in the emerge output:
<console>Command: ##i##n ↵
+
Partition Number: ##i##↵
+
First sector: ##i##↵
+
Last sector: ##i##+32M ↵
+
Hex Code: ##i##EF02 ↵
+
</console>
+
 
+
'''Create Partition 3''' (swap):
+
<console>Command: ##i##n ↵
+
Partition Number: ##i##↵
+
First sector: ##i##↵
+
Last sector: ##i##+4G ↵
+
Hex Code: ##i##8200 ↵
+
</console>
+
 
+
{{fancynote|'''A rule of thumb for swap size is either 2 x RAM or RAM + 1.'''}}
+
 
+
'''Create Partition 4''' (ZFS):
+
<console>Command: ##i##n ↵
+
Partition Number: ##i##↵
+
First sector: ##i##↵
+
Last sector: ##i##↵
+
Hex Code: ##i##bf00 ↵
+
 
+
Command: ##i##p ↵
+
 
+
Number  Start (sector)    End (sector)  Size      Code  Name 
+
1            2048          514047  250.0 MiB  8300  Linux filesystem 
+
2          514048          579583  32.0 MiB    EF02  BIOS boot partition 
+
3          579584        8968191  4.0 GiB    8200  Linux swap 
+
4        8968192      1048575966  495.7 GiB  BF00  Solaris root
+
 
+
Command: ##i##w ↵
+
</console>
+
 
+
=== Format your /boot partition ===
+
  
 
<console>
 
<console>
# ##i##mkfs.ext2 -m 1 /dev/sda1
+
# ##i##emerge --config sys-process/fcron
</console>
+
Configuring pkg...
  
=== Encryption (Optional) ===
+
* This is going to set up fcron to execute check_system_crontabs.
If you want encryption, then create your encrypted vault(s) now by doing the following:
+
* In this configuration, you're no longer free to edit the systab
 
+
  * at your leisure, at it'll be rewritten the moment the crontabs
<console>
+
* are modified.
# ##i##cryptsetup luksFormat /dev/sda4
+
# ##i##cryptsetup luksOpen /dev/sda4 vault_1
+
</console>
+
 
+
{{fancywarning|On some machines, a combination of ZFS and LUKS has caused instability and system crashes.}}
+
 
+
=== Create the zpool ===
+
We will first create the pool. The pool will be named `tank` and the disk will be aligned to 4K sectors:
+
 
+
<console># ##i##zpool create -f -o ashift=12 -o cachefile= -O compression=lz4 -O normalization=formD -m none -R /mnt/funtoo tank /dev/sda4</console>
+
 
+
{{fancyimportant|If you are using encrypted root, change '''/dev/sda4 to /dev/mapper/vault_1'''.}}
+
 
+
 
+
{{fancyimportant|If you have a previous pool that you would like to import, you can do:}}
+
 
+
<console>
+
# ##i##zpool import -f -o cachefile= -R /mnt/funtoo <pool_name>
+
</console>
+
 
+
 
+
=== Create the zfs datasets ===
+
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 (/). 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>
+
Create some empty containers for organization purposes, and make the dataset that will hold /
+
# ##i##zfs create 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/
+
# ##i##zfs create -o mountpoint=/usr/src tank/funtoo/src
+
# ##i##zfs create -o mountpoint=/usr/portage -o compression=off tank/funtoo/portage
+
</console>
+
 
+
 
+
=== Format your swap ===
+
<console>
+
# ##i##mkswap -f /dev/sda3
+
# ##i##swapon /dev/sda3
+
</console>
+
 
+
Now we will continue to install funtoo.
+
 
+
== Installing Funtoo ==
+
 
+
=== Pre-Chroot ===
+
 
+
<console>
+
Go into the directory that you will chroot into
+
# ##i##cd /mnt/funtoo
+
 
+
Make a boot folder and mount your boot drive
+
# ##i##mkdir boot
+
# ##i##mount /dev/sda1 boot
+
</console>
+
 
+
[[Funtoo_Linux_Installation|Now download and extract the Funtoo stage3 ...]]
+
 
+
Once you've extracted the stage3, do a few more preparations and chroot into your new funtoo environment:
+
 
+
<console>
+
Bind the kernel related directories
+
# ##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>
+
 
+
=== In Chroot ===
+
 
+
<console>
+
Create a symbolic link to your mountpoints
+
# ##i##ln -sf /proc/mounts /etc/mtab
+
 
+
Sync your tree
+
# ##i##emerge --sync
+
</console>
+
 
+
=== Add filesystems to /etc/fstab ===
+
 
+
Before we install our kernel in the next section, we will edit the <tt>/etc/fstab</tt> file and make sure our /boot line is correct. This is because portage needs to know where our /boot is so that it can install the files there.
+
 
+
Edit <tt>/etc/fstab</tt>:
+
 
+
<pre>
+
# <fs>                  <mountpoint>    <type>          <opts>          <dump/pass>
+
 
+
/dev/sda1              /boot          ext2            defaults        0 2
+
/dev/sda3              none            swap            sw              0 0
+
</pre>
+
 
+
== Kernel Configuration ==
+
To speed this step up, we will 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>
+
# ##i##emerge bliss-kernel
+
</console>
+
 
+
Now make sure that your <tt>/usr/src/linux symlink</tt> is pointing to this kernel by typing the following:
+
 
+
<console>
+
# ##i##eselect kernel list
+
Available kernel symlink targets:
+
[1]  linux-3.12.13-KS.02 *
+
</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 #'''.
+
 
+
== Installing the ZFS userspace tools and kernel modules ==
+
Emerge {{Package|sys-fs/zfs}}. This package will bring in {{Package|sys-kernel/spl}}, and {{Package|sys-fs/zfs-kmod}} as its dependencies:
+
 
+
<console>
+
# ##i##emerge zfs
+
</console>
+
 
+
Check to make sure that the zfs tools are working. The <code>zpool.cache</code> file that you copied before should be displayed.
+
 
+
<console>
+
# ##i##zpool status
+
# ##i##zfs list
+
</console>
+
 
+
If everything worked, continue.
+
 
+
== Installing & Configuring the Bootloader ==
+
 
+
First we will install GRUB 2:
+
 
+
<console>
+
# ##i##emerge grub
+
</console>
+
 
+
Now install grub to the drive itself (not a partition):
+
 
+
<console>
+
# ##i##grub-install /dev/sda
+
</console>
+
 
+
You should receive the following message:
+
 
+
<console>
+
Installation finished. No error reported.
+
</console>
+
 
+
Checking your /boot folder should reveal a fully loaded grub directory:
+
 
+
<console>
+
# ##i##ls -l /boot/grub
+
total 2520
+
-rw-r--r-- 1 root root    1024 Jan 4 16:09 grubenv
+
drwxr-xr-x 2 root root    8192 Jan 12 14:29 i386-pc
+
drwxr-xr-x 2 root root    4096 Jan 12 14:28 locale
+
-rw-r--r-- 1 root root 2555597 Feb  4 11:50 unifont.pf2
+
</console>
+
 
+
=== Automatic bootloader configuration with bliss-boot ===
+
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. For the purposes of this guide, we will show you how to generate a GRUB 2 configuration.
+
 
+
First install it via the following command:
+
<console>
+
# ##i##emerge bliss-boot
+
</console>
+
 
+
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>
+
# This should be set to the bootloader you installed earlier: (grub2, extlinux, and lilo are the available options)
+
bootloader = "grub2"
+
 
+
# This should be set to the kernel you installed earlier
+
default = "3.12.13-KS.02"
+
</pre>
+
 
+
Scroll all the way down until you find 'kernels'. You will need to add the kernels and the options
+
you want for these kernels.
+
 
+
==== For normal zfs installations ====
+
<pre>
+
kernel = {
+
    '3.12.13-KS.02' : 'root=tank/funtoo/root quiet',
+
}
+
</pre>
+
 
+
==== For encrypted zfs installations ====
+
'''If you are using encryption then you would let the initramfs know:'''
+
 
+
* How do you want to decrypt the drive? ('''enc_type=''')
+
:* 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>
+
kernel = {
+
    '3.12.13-KS.02' : 'root=tank/funtoo/root enc_root=/dev/sda4 enc_type=pass quiet',
+
}
+
</pre>
+
 
+
==== Generate the configuration ====
+
Now that we have configure our '''/etc/bliss-boot/conf.py''' file, we can generate our config. Simply run the following command:
+
 
+
<console>
+
# ##i##bliss-boot
+
</console>
+
 
+
{{fancyimportant|'''For safety reasons, bliss-boot doesn't automatically overwrite /boot/grub/grub.cfg but rather generates the configuration file in your current directory. After you check the file, move it to /boot/grub/grub.cfg'''.}}
+
 
+
== Create the initramfs ==
+
If you are encrypting your drives, then add the "luks" use flag to your package.use before emerging:
+
 
+
<console>
+
# ##i##echo "sys-kernel/bliss-initramfs luks" >> /etc/portage/package.use
+
</console>
+
 
+
Now install the program and run it:
+
<console>
+
# ##i##emerge bliss-initramfs
+
 
+
You can either run it without any parameters to get an interactive menu
+
or you can pass the parameters directly. 1 = zfs, 6 = encrypted zfs, and the kernel name.
+
# ##i##bliss-initramfs 1 3.12.13-KS.02
+
 
+
Your file will be in the current directory.
+
</console>
+
 
+
=== Moving the initrd into the correct location ===
+
Place the generated file into your /boot/kernels/3.12.13-KS.02/ folder. For bliss-boot, the file needs to be called 'initrd' rather than 'initrd-3.12.13-KS.02'.
+
 
+
<console>
+
# ##i##mv initrd-3.12.13-KS.02 /boot/kernels/3.12.13-KS.02/initrd
+
</console>
+
 
+
== Final configuration ==
+
=== Add the zfs tools to openrc ===
+
<console># ##i##rc-config add zfs boot</console>
+
 
+
=== Clean up and reboot ===
+
We are almost done, just clean up, '''set our root password''', and unmount whatever we mounted and get out:
+
 
+
<console>
+
Delete the stage3 tarball that you downloaded earlier so it doesn't take up space.
+
# ##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/sda3
+
 
+
Reboot
+
# ##i##reboot
+
</console>
+
 
+
{{fancywarning|'''Do not export the zpool. Just reboot. ZFS's zpool.cache file is shared between reboots and exporting the pool will cause problems. Exporting the pool is only meant when you want to move the zpool from one machine to another.'''}}
+
 
+
{{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.'''}}
+
 
+
and that should be enough to get your system to boot on ZFS.
+
 
+
== After reboot ==
+
 
+
=== Forgot to reset password? ===
+
==== 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>
+
# ##i##zpool import -f -o cachefile= -R /mnt/funtoo tank
+
# ##i##chroot /mnt/funtoo bash -l
+
# ##i##passwd
+
# ##i##exit
+
# ##i##reboot
+
</console>
+
 
+
==== Using bliss-initramfs ====
+
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 ===
+
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:
+
<console># ##i##zfs snapshot -r tank@install</console>
+
 
+
To see if your snapshot was taken, type:
+
<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):
+
<console># ##i##zfs rollback tank/funtoo/root@install</console>
+
 
+
{{fancyimportant|'''For a detailed overview, presentation of ZFS' capabilities, as well as usage examples, please refer to the [[ZFS_Fun|ZFS Fun]] page.'''}}
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== Troubleshooting ==
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=== Starting from scratch ===
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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:
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<console>
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Destroy the pool and any snapshots and datasets it has
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# ##i##zpool destroy -R -f tank
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This deletes the files from /dev/sda1 so that even after we zap, recreating the drive in the exact sector
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position and size will not give us access to the old files in this partition.
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# ##i##mkfs.ext2 /dev/sda1
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# ##i##sgdisk -Z /dev/sda
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</console>
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Now start the guide again :).
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Rebuilding fcron systab.2013-10-19 21:20:38 
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INFO installing file /tmp/fcrontab.84pova for user systab
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Modifications will be taken into account right now.</console>
  
[[Category:HOWTO]]
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Your cron daemon is now configured to automatically run system cron jobs.
[[Category:Filesystems]]
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[[Category:Featured]]
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__NOTITLE__
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[[Category:System]]

Revision as of 21:00, December 10, 2013

Introduction

Cron daemons allow you to configure certain tasks to be run at specific times. Installing a cron daemon is a good idea because some packages may assume that you have a cron daemon installed and create jobs to update their databases with a cron daemon. There are several different loggers available to Funtoo users:

  • Fcron
  • Cronie
  • Vixie-Cron

Installation

To install the cron daemon, run the following command:

#  emerge --ask fcron

These are the packages that would be merged, in order:

Calculating dependencies... done!
[ebuild  N     ] sys-process/cronbase-0.3.2-r1
[ebuild  N     ] sys-process/fcron-3.1.2-r2  USE="mta pam readline system-crontab -debug (-selinux)" LINGUAS="-fr" 

Would you like to merge these packages? [Yes/No] yes

Now enable the cron init script so that is starts when your system boots, and enable the cron daemon:

# rc-update add fcron default
 * service fcron added to runlevel default
# rc
 * Caching service dependencies ...              [ ok ]
 * Starting fcron ...                            [ ok ]

System Cron Jobs

After the cron daemon has been emerged, you may see a message to run emerge --config to configure your cron daemon to process system cron jobs. System cron jobs are scripts that are installed by various packages into the following directories:

  • /etc/cron.hourly
  • /etc/cron.daily
  • /etc/cron.weekly
  • /etc/cron.monthly

For example, you should find a /etc/cron.daily/man-db script that is installed by the man-db ebuild. This system cron job's purpose is to update the man cache every day, and it will run only if you enable your cron daemon to manage system cron jobs.

You may choose to enable your cron daemon so that it runs system cron jobs, or choose not to. Enabling a cron daemon to run system cron jobs will result in a bit more disk and CPU activity on your system, but should ensure that the system runs more optimally most of the time (proper caching of man pages, etc.) It is recommended for most systems, but your system will still function without system cron jobs active.

If you would like to have your system run system cron jobs, use emerge --config as specified in the emerge output:

# emerge --config sys-process/fcron
Configuring pkg...

 * This is going to set up fcron to execute check_system_crontabs.
 * In this configuration, you're no longer free to edit the systab
 * at your leisure, at it'll be rewritten the moment the crontabs
 * are modified.

Rebuilding fcron systab.2013-10-19 21:20:38  
INFO installing file /tmp/fcrontab.84pova for user systab
Modifications will be taken into account right now.

Your cron daemon is now configured to automatically run system cron jobs.