Can Snapraid make the whole system unresponsive?

    • OMV 3.x
    • Can Snapraid make the whole system unresponsive?


      I just tried to run a snapraid sync for the first time (from the control panel, and it got as far as scanning the second disk, after which I received a "communication failure" popup. The server also didn't react to console inputs, ssh, or smb access.

      I rebooted (using the hardware button) and tried again, this time from the console, the result is the same:

      Self test...
      Loading state from ...
      Scanning disk Data1...
      Scanning disk Data2...

      I noticed that the HDD led is still on, and I have to admit to having an obscene amount of small files on that disk (~800 GB in 600k Files in 100k folders).

      Can it be that Snapraid is just traversing the disk? Do I have to start it "nice"? In my experience, linux doesn't get unresponsive just because of one process. However, I currently only have 2GB Ram, this might be a bottleneck.
    • Sean wrote:

      Can it be that Snapraid is just traversing the disk? Do I have to start it "nice"?
      If you want to have a clue what's going on you could 'apt install sysstat iozone3 ionice lsof' and then use 'iostat 5' in a separate shell to see whether Linux is stuck in IO (then it can become absolutely unresponsive, watch the %iowait value), the other tools are there to test/check for performance and open files and with ionice you could try to avoid bein stuck in IO a little bit.

      Since I'm using OMV on very slow devices I use btrfs + snapshots + incremental sending the snapshots to another disk/host. Pretty much same results as snapraid without any IO load.
    • Thanks for the replies. I will just let it continue. Now I wish I hadn't pushed the reset button this morning after it ran for the night...

      If it's only so slow one time, it's OK. It's a large amount of files, but it's all the photos, documents etc. I collected over 20 years. So in the future the growth will be quite slow.

      Talking about snapraid, am I right in thinking that if I want it to sync regularly, I have to use "Scheduled jobs" and add a weekly "snapraid sync" command? Does it make sense to invoke it with "nice -n 15 snapraid sync"?