====== ZFS Filesystem Fragmentation ======

ZFS does not have a huge problem with fragmentation.  However, over time and especially when the ZFS filesystem gets over 70% full, fragmentation occurs.

:!: The ''FRAG'' column of a ''zpool list'' command shows how fragmented the **free space** is.

  * https://utcc.utoronto.ca/~cks/space/blog/solaris/ZFSZpoolFragmentationMeaning

:!: There is no 'defragging tool' for ZFS.

The easiest and most sure way to defragment a ZFS pool is to use ''zfs send'' and ''zfs recv'' to copy the data out of the fragmented pool and into a new, unfragmented pool.  This is not unlike other filesystems.

https://pthree.org/2012/12/20/zfs-administration-part-xiii-sending-and-receiving-filesystems/

http://docs.oracle.com/cd/E19253-01/819-5461/gbchx/index.html

http://docs.oracle.com/cd/E19253-01/819-5461/gbinw/