I was considering enabling TRIM for my SSD Mirror pool, but the description text for "Auto TRIM" somewhat confuses me:
Enable for TrueNAS to periodically review data blocks and identify empty blocks of obsolete blocks that can be deleted. Unset to incorporate day block overwrites when a device write is started (default).
How does this translate into the technical ZFS world?
It's clear that checking the setting will enable `autotrim=on` on the respective ZFS pool. But there are arguments for preferring regular manual trims over autotrim (small performance overhead, small amounts not trimmed, see https://serverfault.com/a/1047815).
Now my actual question:
The 2nd bold part of the sentence leaves me quite puzzled - when _unset_, day block overwrites (?) happen when a device write is started (?).
What is this even supposed to mean?
The "day block overwrite" hints at something occuring daily, but as far as I can tell from the output of `zpool stats -t <NAME` shows that no manual trims have happened, so it cannot mean that.
In general, is creating a custom cron (e.g. weekly) running `zpool trim <NAME>` a reasonable solution over checking "Auto TRIM"?
Enable for TrueNAS to periodically review data blocks and identify empty blocks of obsolete blocks that can be deleted. Unset to incorporate day block overwrites when a device write is started (default).
How does this translate into the technical ZFS world?
It's clear that checking the setting will enable `autotrim=on` on the respective ZFS pool. But there are arguments for preferring regular manual trims over autotrim (small performance overhead, small amounts not trimmed, see https://serverfault.com/a/1047815).
Now my actual question:
The 2nd bold part of the sentence leaves me quite puzzled - when _unset_, day block overwrites (?) happen when a device write is started (?).
What is this even supposed to mean?
The "day block overwrite" hints at something occuring daily, but as far as I can tell from the output of `zpool stats -t <NAME` shows that no manual trims have happened, so it cannot mean that.
In general, is creating a custom cron (e.g. weekly) running `zpool trim <NAME>` a reasonable solution over checking "Auto TRIM"?
Last edited: