On Mon, Aug 19, 2019 at 11:18:13AM +0200, Paolo Valente wrote: > Solving this kind of problem is one of the goals of the BFQ I/O scheduler [1]. > Have you tried? If you want to, then start by swathing to BFQ in both the > physical and the virtual block devices in your stack. I sure was not aware of it, thank you for pointing it out. > Thanks, > Paolo > > [1] https://algo.ing.unimo.it/people/paolo/BFQ/ I did the following below and when the swraid is rebuilding, I'm still getting terrible overall throughput: newmagic:~# hdparm -t /dev/md2 /dev/md2: HDIO_DRIVE_CMD(identify) failed: Inappropriate ioctl for device Timing buffered disk reads: 2 MB in 5.76 seconds = 355.42 kB/sec I think things hang a bit less, which I suppose it good, but the system is still unusable overall. newmagic:~# modprobe bfq newmagic:~# for i in /sys/block/*/queue/scheduler; do echo $i; echo bfq > $i; cat $i; done /sys/block/bcache0/queue/scheduler none /sys/block/md0/queue/scheduler none /sys/block/md1/queue/scheduler none /sys/block/md2/queue/scheduler none /sys/block/md3/queue/scheduler none /sys/block/sda/queue/scheduler [bfq] none /sys/block/sdb/queue/scheduler [bfq] none /sys/block/sdc/queue/scheduler [bfq] none /sys/block/sdd/queue/scheduler [bfq] none /sys/block/sde/queue/scheduler [bfq] none /sys/block/sdf/queue/scheduler [bfq] none /sys/block/sdg/queue/scheduler [bfq] none /sys/block/sdh/queue/scheduler [bfq] none /sys/block/sdi/queue/scheduler [bfq] none /sys/block/sr0/queue/scheduler [bfq] none Thanks, Marc -- "A mouse is a device used to point at the xterm you want to type in" - A.S.R. Microsoft is to operating systems .... .... what McDonalds is to gourmet cooking Home page: http://marc.merlins.org/
