zfs:filesystems:set_properties_for_a_filesystem
Table of Contents
ZFS - Filesystems - Set Properties for a Filesystem
Many Properties can be set.
Compression
sudo zfs set compression=on testpool/projects
NOTE: The default Compression is lz4.
- lz4 is significantly faster than the other options while still performing well;
- lz4 is also the safest choice.
The compression level can be changed if required:
sudo zfs set compression=gzip-9 testpool
The compression type can be changed too:
sudo zfs set compression=lz4 testpool
The compression level can be checked:
sudo zfs get compressratio
Copies / Ditto Blocks
Ditto blocks create more redundant copies of data to copy, just for more added redundancy.
- With a storage pool of just one device, ditto blocks are spread across the device, trying to place the blocks at least 1/8 of the disk apart.
- With multiple devices in a pool, ZFS tries to spread ditto blocks across separate VDEVs.
- 1 to 3 copies can be can be set.
sudo zfs set copies=3 testpool/projects
NOTE: This sets 3 copies on testpool/projects.
Deduplication
ZFS dedup will discard blocks that are identical to existing blocks and will instead use a reference to the existing block.
- This saves space on the device but comes at a large cost to memory.
- The dedup in-memory table uses ~320 bytes per block.
- The greater the table is in size, the slower write performance becomes.
sudo zfs set dedup=on testpool/projects
NOTE: There are pros and cons to deduping.
- Generally, De-duplication is almost never worth the performance penalty.
Mount Point
zfs set mountpoint=/test testpool/projects df -h |grep /test
Quota
sudo zfs set quota=10G testpool/projects
NOTE: This sets a maximum quota of 10 gigabytes.
- The Filesystem cannott use more than this amount.
Reservations
sudo zfs set reservation=200m testpool/tmp
NOTE: This much space is reserved for the Filesystem.
- It will not be available to other Filesystems.
- When a Quota is defined first, a reservation cannot be higher than quota.
zfs/filesystems/set_properties_for_a_filesystem.txt · Last modified: 2021/10/13 23:09 by peter