Klaus Frank10h ago

I really don't get this interaction between "sync" and "rsync". Tried it a few more times and it doesn't happen always but sometimes the "sync" gets stuck until rsync is finished completely. Even if it has yet to touch e.g. 3TB of data.

WTF?!?

Anyone seeing similar things or is there something else at play here too?

#gnu #Linux #coreutils #rsync #NixOS

Show threadRaito Bezarius10h ago
@agowa338 unfair SSD scheduling at play
Show threadKlaus Frank10h ago
@raito What exactly do you mean with "SSD"? There is no SSD involved only HDDs (compressed btrfs > luks2 > lvm raid 5 > 4x HDDs)
Show threadRaito Bezarius10h ago
@agowa338 unfair scheduling on the IO then
Show threadKlaus Frank10h ago
@raito Queue scheduler "/sys/block/sd*/queue/scheduler" is currently set to the default "none [mq-deadline] kyber" for all 8 disks (the 4 at the source and the 4 at the destination) and except for rsync and sync there are no other applications doing any IO (didn't check kernel threads, but LVM, btrfs, ... should always have higher priority than rsync, right, right?)
Show threadRaito Bezarius
@agowa338 priority only make sense when you consider a scheduler
11:18amWeb
Show threadKlaus Frank9h ago

@raito

You make me realise that I don't understand way less about IO scheduling in Linux than I thought.