> Il giorno 19 ago 2019, alle ore 18:40, Marc MERLIN <marc@xxxxxxxxxxx> ha scritto: > > 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. > Ok, I'm sorry it didn't help. Unless someone spots the problem somewhere outside BFQ, I'm willing to analyze this apparently tough scenario, as an opportunity to improve BFQ. If fine for you, just contact me offline. Good luck! Paolo > > 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/
