On 9/2/25 17:41, Dan Ritter wrote:
From what I have seen on FreeBSD ZFS, under load ZFS can consume as much memory as it needs. For storage servers, this is exactly what I want -- I paid for that memory, I want ZFS to use it. But, I have little experience with ZFS on workstations; where many processes are competing for memory. AIUI there are tunables for ZFS, so you have options.If you set dedup, you need lots of RAM, or performance plummets on writes.
Do you have any experience with ZFS dedup when the pool has a special or dedup vdev?
I added a special vdev mirror of two Intel SSD 520 Series 180 GB 2.5" SATA to each server on the last rebuild (with special_small_blocks=16K), and the improvement was noticeable.
If you don't set dedup, you can generally set options like: # Min 512MB / Max 8GB Limit on ZFS RAM usage (ARC) options zfs zfs_arc_min=536870912 options zfs zfs_arc_max=8589934592 in your /etc/modprobe.d/zfs.conf For a lot of small workloads, 512M - 1G works well.
Thank you for the suggestions. :-) David