Differences between revisions 4 and 5

BTRFS filesystem

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

HP Server Raid tools

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-  ⇤ ← Revision 4 as of 2015-05-25 05:39:34 → 
  Size: 987
  Editor: PieterSmit
  Comment:
+   ← Revision 5 as of 2015-07-02 18:59:49 → ⇥
  Size: 1429
  Editor: PieterSmit
  Comment:
-Deletions are marked like this.
+Additions are marked like this.
 Line 6:
+ * 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().