Replying in here because apparently I’m limited to 3 replies in the same thread for some reason:
It has now been about a day and a half since I applied the fix to limit ZFS RAM usage to 50% of total available system RAM.
It has completely solved all of the performance issues I was experiencing with my system.
- Middlewared is now nowhere to be seen in the “top” processes list in a shell window
- Swap hasn’t been touched at all since I made the change
- CPU usage is entirely back to normal
- There has been no sporadic dumping of writes to the SSD housing my SCALE install
- The UI is back to being instantly responsive, as was the case on Cobia
I can only conclude that whatever ZFS is forcing to be kicked out of RAM and run from swap, my primary culprit would be the iX middleware, causes the extremely poor performance. Something a bit less than “total system RAM minus 1GB” is probably a better way to go, perhaps allowing ZFS to use 75% of total system RAM or such, or alternatively something of an internal whitelist that says “when under RAM pressure, don’t evict these processes automatically:…”