Proxmox 6 on home NAS - SLOOOWWWW


Renowned Member
I decided to test Proxmox 6 on my home PC where I installed 4 HD (8Tb) that I setup with RAIDZ1.
From the start the speed of the raid set was just terrible but I managed to speed it up somewhat by using "zfs set sync=disabled rpool".

Now I'm testing other methods to speed up the setup. Maybe adding a SDD drive to helpout ZFS?

Any ideas?
Depending on its write performance, that SSD might be okay for the Intent Log (more or less write cache). But you probably need to reset your expectations because, you're not going to see good performance with that system.

Do some IOPS calculations and you'll see why. Especially look at write performance. o_O

If you want decent performance, try mirrored vdevs with the SSD (if decent write performance).

On the plus side, it will be a good learning experience for tuning ZFS and Linux.
The problem appears to be zfs_arc_max.
Every boot seems to reset the amount of memory I have reserved to ZFS to 0.
This command sets available memory for ZFS back to 8Gb and speeds up the storage considerably.
echo 8000000000 > /sys/module/zfs/parameters/zfs_arc_max
Turns out this had nothing to do with ZFS. It's IRQ/ACPI problem on old motherboard BIOS that causes "kernel: irq 18: nobody cared (try booting with the "irqpoll" option)" error message. After that the HD's just slow to crawl. Since there are no updates to the BIOS my attempt to turn this old HardWare to home NAS system seems doomed. :(


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