Differences between revisions 5 and 14 (spanning 9 versions)

BTRFS filesystem

Btrfs space calculator http://carfax.org.uk/btrfs-usage/
Create a raid1 mirror disk setup raid1 for both data and metadata
- mkfs.btrfs -m raid1 -d raid1 /dev/sdb /dev/sdc /dev/sdd /dev/sde
- Now find uuid with sudo blkid /dev/sd*
  - Add more hd's
    - ```
           btrfs device scan
           btrfs device add /dev/sdc2 /
           btrfs filesystem balance /
           btrfs balance start -dconvert=raid1 -mconvert=raid1 /
```
reflinks
- cp --reflink name1 name4
- reflinks are supported by BTRFS and OCFS2 and support transparent copy on write which is especially useful for snapshotting.
- Note that since separate inodes are used, one can have different permissions to access the same data.
- Reflinks have the same use as hardlinks, but are more space efficient and generally handle all subsequent operations on a file, not just unlink().
If you have virtual images on a btrfs, cow(copy on write) will cause a lot of fragmentation, turn it of for the directory of file with
- this disables cow(fragmentation) and also crc calculations on the files.
  - ```
       chatter +C /path
```

defrag with

   btrfs filesystem defragment /path/file

or faster for large files

     cp --reflink=never vbox.vdi vbox.new.vdi ; rm vbox.vdi ;

Create raid array, raid1 all data mirrored once.
- # mkfs.btrfs -m raid1 -d raid1 -L root /dev/disk/by-label/root1 /dev/disk/by-label/root2 /dev/disk/by-lab

el/root3 /dev/disk/by-label/root4

Mount options, add compress
subvolumes
- mount option subvol=homevol

Install on multi disk

Will install on multiple disks
- ```
   sudo dpkg-reconfigure grub-pc 
```
Use uuid , same for all disks.
- ```
   sudo blkid /dev/sd* 
```

BTRFS maintenace

SCRUB disks in background, recovering for good copy in raid1 config

   sudo btrfs filesystem show
   sudo btrfs filesystem df /
   sudo btrfs scrub start /
   sudo btrfs scrub status -d /

Resize
1. Increase the partition (lvm or fdisk)
2. find the <devid> (disk number) # btrfs filesystem show
3. btrfs filesystem resize <devid>:max /

Error trying to convert to raid0

   # btrfs balance start -dconvert=raid0 /home
   ERROR: error during balancing '/home' - No space left on device
   In dmesg  btrfs: 262 enospc errors during balance

  sudo btrfs fi balance start -dusage=10 /
  btrfs balance start -dconvert=raid0 /home

HP Server Raid tools

http://dmatwork.blogspot.com/2010/07/installation-of-hp-array-configuration.html

...

-  ⇤ ← Revision 5 as of 2015-07-02 18:59:49 → 
  Size: 1429
  Editor: PieterSmit
  Comment:
+   ← Revision 14 as of 2016-02-26 08:53:10 → ⇥
  Size: 2825
  Editor: PieterSmit
  Comment: Add no space left problem.
-Deletions are marked like this.
+Additions are marked like this.
 Line 6:
+ * Btrfs space calculator http://carfax.org.uk/btrfs-usage/
 * Create a raid1 mirror disk setup raid1 for both data and metadata
   {{{ mkfs.btrfs -m raid1 -d raid1 /dev/sdb /dev/sdc /dev/sdd /dev/sde }}}
   * Now find uuid with {{{ sudo blkid /dev/sd* }}} 
     * Add more hd's
       {{{
       btrfs device scan
       btrfs device add /dev/sdc2 /
       btrfs filesystem balance /
       btrfs balance start -dconvert=raid1 -mconvert=raid1 /

       }}}
-Line 33:
+Line 45:
+== Install on multi disk ==
 * Will install on multiple disks
   {{{ 
   sudo dpkg-reconfigure grub-pc }}}
 * Use uuid , same for all disks. 
   {{{
   sudo blkid /dev/sd* }}}

== BTRFS maintenace ==
 * SCRUB disks in background, recovering for good copy in raid1 config
   {{{
   sudo btrfs filesystem show
   sudo btrfs filesystem df /
   sudo btrfs scrub start /
   sudo btrfs scrub status -d /
   }}}
 * Resize
   1. Increase the partition (lvm or fdisk)
   2. find the <devid> (disk number) # btrfs filesystem show
   3. btrfs filesystem resize <devid>:max /

 * Error trying to convert to raid0
   {{{
   # btrfs balance start -dconvert=raid0 /home
   ERROR: error during balancing '/home' - No space left on device
   In dmesg  btrfs: 262 enospc errors during balance
   }}}
   * FIX
  {{{
  sudo btrfs fi balance start -dusage=10 /
  btrfs balance start -dconvert=raid0 /home
  }}}