Thanks for your reply. Does it also not work with Amazon EBS and SAN based storage? Regards - Himadri On Tue, Apr 26, 2016 at 12:01 AM, nborisov <n.borisov.lkml@xxxxxxxxx> wrote: > > > On 25.04.2016 20:53, Himadri Sarkar wrote: >> Hi, >> >> I was doing some experiments to test out blkio with the following >> setups and was unable to get the expected behavior. It will be great >> if someone can help me understand what might have gone wrong with my >> setup. >> >> Setup 1 >> hardware: d2.xlarge machine on aws (It has 3 * 2 TB hdd) >> logical volume: setup an lvm to use 2 disks out of 3 >> file system: xfs >> IO Scheduler: cfq >> blkio weights: test1 has weight 1000, test2 has weight 500 >> >> Now when I run the tests as given in >> https://www.kernel.org/doc/Documentation/cgroup-v1/blkio-controller.txt >> using dd (I only executed read tests on already written files) >> I found that both the processes were getting equal time share >> (blkio.time) and serviced bytes (blkio.io_service_bytes) irrespective >> of differential weights. >> >> Now when I modified the setup by not having lvm setup and just >> creating a 2TB file system out of a single hdd it worked i.e. serviced >> bytes were in the ratio 2 : 1 >> >> On the other hand when I tested read with fio >> >> specifically >> >> fio --randrepeat=1 --ioengine=libaio --direct=1 --gtod_reduce=1 >> --name=test2 --filename=file2 --bs=4k --iodepth=64 --size=4G >> --readwrite=randrw --rwmixread=100 >> >> Then also it worked even with the lvm setup. Which makes be believe >> that with Setup 1 it is not working due to buffered reads. (But then >> the same thing also worked without lvm) > > This is a well-known limitation to LVM, which supposedly was fixed in a > recent kernel. For more information check this email thread: > https://www.redhat.com/archives/dm-devel/2016-February/msg00183.html > > Then a patch was proposed in the following thread: > https://www.redhat.com/archives/dm-devel/2016-March/msg00006.html > > This was tested by me and the proportional-based limits were working, > provided that the devices hosting the LVM VG were using CFQ as their io > scheduler. > > Regards, > Nikolay -- To unsubscribe from this list: send the line "unsubscribe cgroups" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
