Related articles * [File systems](/index.php/File_systems "File systems") [Reiser4](https://en.wikipedia.org/wiki/Reiser4 "wikipedia:Reiser4") is the successor filesystem for ReiserFS, developed from scratch by [Namesys](https://en.wikipedia.org/wiki/Namesys "wikipedia:Namesys") and [Hans Reiser](https://en.wikipedia.org/wiki/Hans_Reiser "wikipedia:Hans Reiser"). It is very efficient for handling small files (often used in `/var` for this purpose) and includes features such as cheap transparent compression and block suballocation. Because it is an atomic file system "your file system operations either entirely occur, or they entirely don't, and they do not corrupt due to half occurring." [Benchmarks](http://vizzzion.org/?id=reiser4) with other linux filesystems are also available. ## Contents * [1 Important Notes](#Important_Notes) * [2 Packages](#Packages) * [3 Moving to Reiser4](#Moving_to_Reiser4) * [3.1 Sample system](#Sample_system) * [3.2 Formatting](#Formatting) * [3.3 Copy system](#Copy_system) * [3.4 /etc/fstab:](#.2Fetc.2Ffstab:) * [4 Bootloader Examples](#Bootloader_Examples) * [4.1 /boot/grub/grub.cfg:](#.2Fboot.2Fgrub.2Fgrub.cfg:) * [4.2 /etc/lilo.conf:](#.2Fetc.2Flilo.conf:) * [5 Troubleshooting](#Troubleshooting) ## Important Notes * Reiser4 requires a patched kernel * It consumes a little more CPU than other filesystems * Even [LILO](/index.php/LILO "LILO") as the only bootloader officially supporting Reiser4 seems to have issues with it when `/boot` is formatted as Reiser4 * It is still not considered stable **Note:** In systemd219, [Access Control Lists](/index.php/Access_Control_Lists "Access Control Lists") is not enabled by default on Reiser4 partition. If you put /var on such a filesystem, you will need to do so or [Tmpfs](/index.php/Tmpfs "Tmpfs") will not be mounted correctly. See for details [Systemd#Troubleshooting](/index.php/Systemd#Troubleshooting "Systemd") **Tip:** [Gparted LiveCD](http://gparted.sourceforge.net/livecd.php) is a small Linux distribution booting straight into Gparted. It also supports Reiser4 ## Packages 1\. [Install](/index.php/Install "Install") the [reiser4progs](https://aur.archlinux.org/packages/reiser4progs/) package 2\. You will need a reiser4 patched kernel. Patches can be found here [https://sourceforge.net/projects/reiser4/files/](https://sourceforge.net/projects/reiser4/files/) 3\. Bootloader *(Optional, only needed if you want to format your `/` (root) as **reiser4**)* **Note:** Backing up your bootloader configuration file should be considered. a) **Recommended:** make a small (as mentioned above, 20-200mb) partition for `/boot` with a filesystem other than Reiser4 with [GParted](/index.php/GParted "GParted"), and then copy your `/boot` folder to the partition. Update your bootloader config accordingly, eg. with [Grub2](/index.php/Grub2 "Grub2") do: ``` # grub-mkconfig -o /boot/grub/grub.cfg ``` b) If you wish to put everything including `/boot` on a Reiser4 partition you will need to use [LILO](/index.php/LILO "LILO"). This is not advised, as you will probably get an error when trying to update `lilo.conf`: ``` # lilo ``` 4\. Reboot **Note:** The following steps are for using Reiser4 as your / (root). If you just want to use Reiser in /var (or whatever) you should modify the following instructions according to your needs. ## Moving to Reiser4 In the next steps we will copy the data from your current root partition to the new Reiser4 partitions. Make sure you have enough disk space on the Reiser4 partition with: ``` # df -h ``` ### Sample system ``` # fdisk -l * /dev/sda1: (10 Gb, 5 Gb free); Reiserfs /mnt/reiser4 * /dev/sda2: (10 Gb, 10 Gb free); Reiser4 / * /dev/sda3: (200 Mb, 180 Mb free); ext2 /boot ``` ### Formatting Run the following commands: ``` mkfs.reiser4 /dev/sdaX mkdir /mnt/reiser4 mount -t reiser4 /dev/sdaX /mnt/reiser4 ``` **Note:** With **X** being your partition number! It is recommended that you use the Cryptcompress plugin by formatting with the following command: ``` mkfs.reiser4 -o create=ccreg40,compress=lzo1 /dev/sda**X** ``` ### Copy system Once the partition is formatted, copy you current system to the new partition and create the system directories. You may either do this from Arch Linux, or **to make it easier** (so that you do not have to use makedev later), just **boot up with the [Gparted LiveCD](http://gparted.sourceforge.net/livecd.php) and mount both your new Reiser4 partition and your current root partition. Then, just copy everything over (as root) like so:** ``` cd /mnt mkdir oldroot mkdir reiser4 mount /dev/sdaX oldroot mount /dev/sdaY reiser4 (the Reiser4 partition) cp -R -a /mnt/oldroot/* /mnt/reiser4/ ``` Then, you need to mount your `/boot` partition, and if you have not already, copy `/boot` from your original root partition over to it. **Note:** It is suggested to empty your /boot from the Reiser4 partition to use it as a mountpoint, which is reflected later in your fstab ``` mkdir bootpart mount /dev/sdaZ bootpart cp -R -a /mnt/oldroot/boot/* /mnt/bootpart/ ``` Do not forget to edit your bootloader's config appropriately (see examples at the bottom of the article). **Note:** In case you upgraded grub before rebooting you may need to manually install grub to your /boot partition, otherwise, things may break and prevent you from booting. In this case using a LiveCD to Chroot and would be your last hope. ### /etc/fstab: Note: If you can confirm that Reiser4 works for you, you should format the old root partition. ``` # # /etc/fstab: static file system information # # /dev/sda1 / reiser4 defaults,noatime,notail 0 1 /dev/sda2 /mnt/oldroot ext4 defaults 0 0 /dev/sda3 /boot ext2 defaults 0 1 ``` ## Bootloader Examples #### /boot/grub/grub.cfg: ``` # (0) Arch Linux title Arch Linux set root=(hd0,msdos3) kernel /vmlinuz-linux root=/dev/sda3 ro noatime notail acl init=/usr/bin/bootchartd initrd /initramfs-linux.img # (1) Arch Linux title Arch Linux Fallback set root=(hd0,msdos3) kernel /vlinuz-linux root=/dev/sda3 ro initrd /initramfs-linux-fallback.img ``` Run `grub-mkconfig` to update your config: ``` # grub-mkconfig -o /boot/grub/grub.cfg ``` #### /etc/lilo.conf: ``` # # /etc/lilo.conf # boot=/dev/hda # This line often fixes L40 errors on bootup # disk=/dev/hda bios=0x80 default=Arch4 timeout=20 lba32 prompt compact image=/boot/vmlinuz-linux label=Arch4 root=/dev/hda5 append="video=vesafb:1024x768-24@56,ywrap,mtrr splash=verbose,theme:darch console=tty1 resume2=swap:/dev/hdb1" initrd=/boot/initramfs-linux.img read-only image=/boot/vmlinuz-linux label=Arch root=/dev/hda3 append="video=vesafb:1024x768-24@56,ywrap,mtrr splash=verbose,theme:darch console=tty1 resume2=swap:/dev/hdb1" initrd=/boot/initramfs-linux.img read-only ``` Run **lilo** to update your config: ``` # lilo ``` ## Troubleshooting * Permissions: chown -R username.group * If you have problem with **su** command after the change of fs, you should reinstall **coreutils** package.