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--- zfs:filesystems:set_properties_for_a_filesystem [2021/10/13 13:20] – created peter
+++ zfs:filesystems:set_properties_for_a_filesystem [2021/10/13 22:09] (current) – [Deduplication] peter
@@ Line 1: / Line 1: @@
 ====== ZFS - Filesystems - Set Properties for a Filesystem ======
+Many Properties can be set.
+----
+===== Compression =====
+<code bash>
+sudo zfs set compression=on testpool/projects
+</code>
+<WRAP info>
+**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:
+<code bash>
+sudo zfs set compression=gzip-9 testpool
+</code>
+The compression type can be changed too:
+<code bash>
+sudo zfs set compression=lz4 testpool
+</code>
+The compression level can be checked:
+<code bash>
+sudo zfs get compressratio
+</code>
+</WRAP>
+----
+===== 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.
+<code bash>
+sudo zfs set copies=3 testpool/projects
+</code>
+<WRAP info>
+**NOTE:**  This sets 3 copies on testpool/projects.
+</WRAP>
+----
+===== 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.
+<code bash>
+sudo zfs set dedup=on testpool/projects
+</code>
+<WRAP info>
+**NOTE:**  There are pros and cons to deduping.
+  * Generally, De-duplication is almost never worth the performance penalty.
+</WRAP>
+----
+===== Mount Point =====
+<code bash>
+zfs set mountpoint=/test testpool/projects
+df -h |grep /test
+</code>
+----
+===== Quota =====
+<code bash>
+sudo zfs set quota=10G testpool/projects
+</code>
+<WRAP info>
+**NOTE:**  This sets a maximum quota of 10 gigabytes.
+  * The Filesystem cannott use more than this amount.
+</WRAP>
+----
+===== Reservations =====
+<code bash>
+sudo zfs set reservation=200m testpool/tmp
+</code>
+<WRAP info>
+**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.
+</WRAP>