ZFS speed issues

1st Official Post

    Hi!
    I have intel celeron n3150 (4 cores @1.6Ghz), 16Gb DDR3 ram and 4x1TB HDD`s with 128Mb ccache each. OMV 6 freshly installed, Proxmox 5.15.39.4 - 4 kernel and ZFS 6.0.11 plugin
    Before that I had same configuration, bu with 8 Gb RAM and RAID5, there were huge Load average (even 16 and more) when file operations, such as copying large files.
    I was offered to move to ZFS, what i did.
    Issue is like one with RAID 5, but even worse. When I copy large files (40Gb BD-rips) over the 1Gb network, speed drops from 112mb/s to almost 15mb/s, after some time it restores to about 100mb/s, and again drops to 20-50. Load average is about OK, holds at ~ 3 -4. With peaks >10. Memory usage more than 8 Gb, witch is kinda OK, since I have 16Gb`s. CPU loads not much, than 50% in peak
    I tried to change configuration, build test machine with some lenovo motherboard , core I7 4770, 16 gb RAM and 4x256Gb SSD. Tried both, ZFS and RAID5, Issues are the same as i wrote before, speed drops, huge LA.
    Am I the only one, expecting such issues, or it`s normal behavior ?
    Thanks.

    • Official Post
    Quote from dtr

    When I copy large files (40Gb BD-rips) over the 1Gb network, speed drops from 112mb/s to almost 15mb/s, after some time it restores to about 100mb/s, and again drops to 20-50. Load average is about OK, holds at ~ 3 -4. With peaks >10. Memory usage more than 8 Gb, witch is kinda OK, since I have 16Gb`s. CPU loads not much, than 50% in peak

    Check the iowait indexes. If there is any process that causes crashes (for example jellyfin extracting keyframes...) it can drop the speed.

    You may also have processes on your own PC that slow down network copy speeds, it happens to me when I have Handbrake running on my PC. If I pause the job the speeds return to normal.

Participate now!

Don’t have an account yet? Register yourself now and be a part of our community!

Register Yourself Login