2014-06-13 21:23 GMT+08:00 Andrey Korolyov <and...@xdel.ru>: > On Fri, Jun 13, 2014 at 7:09 AM, Ke-fei Lin <k...@kfei.net> wrote: > > Hi list, > > > > I deployed a Windows 7 VM with qemu-rbd disk, and got an unexpected > booting > > phase performance. > > > > I discovered that when booting the Windows VM up, there are consecutive > ~2 > > minutes that `ceph -w` gives me an interesting log like: "... 567 KB/s > rd, > > 567 op/s", "... 789 KB/s rd, 789 op/s" and so on. > > > > e.g. > > 2014-06-05 15:47:43.125441 mon.0 [INF] pgmap v18095: 320 pgs: 320 > > active+clean; 86954 MB data, 190 GB used, 2603 GB / 2793 GB avail; 765 > kB/s > > rd, 765 op/s > > 2014-06-05 15:47:44.240662 mon.0 [INF] pgmap v18096: 320 pgs: 320 > > active+clean; 86954 MB data, 190 GB used, 2603 GB / 2793 GB avail; 568 > kB/s > > rd, 568 op/s > > ... (skipped) > > 2014-06-05 15:50:02.441523 mon.0 [INF] pgmap v18186: 320 pgs: 320 > > active+clean; 86954 MB data, 190 GB used, 2603 GB / 2793 GB avail; 412 > kB/s > > rd, 412 op/s > > > > Which shows the number of rps is always the same as the number of ops, > i.e. > > every operation is nearly 1KB, and I think this leads a very long boot > time > > (takes 2 mins to enter desktop). But I can't understand why, is it an > issue > > of my Ceph cluster? Or just some special I/O patterns in Windows VM > booting > > process? > > > > In addition, I know that there are no qemu-rbd caching benefits during > boot > > phase since the cache is not persistent (please corrects me), so is it > > possible to enlarge the read_ahead size in qemu-rbd driver? And does this > > make any sense? > > > > And finally, how can I tune up my Ceph cluster for this workload (booting > > Windows VM)? > > > > Any advice and suggestions will be greatly appreciated. > > > > > > Context: > > > > 4 OSDs (7200rpm/750GB/SATA) with replication factor 2. > > > > The system disk in Windows VM is NTFS formatted with default 4K block > size. > > > > $ uname -a > > Linux ceph-consumer 3.11.0-22-generic #38~precise1-Ubuntu SMP Fri > May 16 > > 20:47:57 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux > > > > $ ceph --version > > ceph version 0.80.1 (a38fe1169b6d2ac98b427334c12d7cf81f809b74) > > > > $ dpkg -l | grep rbd > > ii librbd-dev 0.80.1-1precise > > RADOS block device client library (development files) > > ii librbd1 0.80.1-1precise > > RADOS block device client library > > > > $ virsh version > > Compiled against library: libvir 0.9.8 > > Using library: libvir 0.9.8 > > Using API: QEMU 0.9.8 > > Running hypervisor: QEMU 1.7.1 () > > > > _______________________________________________ > > ceph-users mailing list > > ceph-users@lists.ceph.com > > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > > > > Hi, > > If you are able to leave only this VM in cluster scope to check, > you`ll perhaps may use virsh domblkstat accumulated values to compare > real number of operations. >
Thanks, Andrey. I tried `virsh domblkstat <vm> hda` (only this VM in whole cluster) and got these values: hda rd_req 70682 hda rd_bytes 229894656 hda wr_req 1067 hda wr_bytes 12645888 hda flush_operations 0 (These values became stable after ~2 mins) While the output of `ceph -w` is attached at: http://pastebin.com/Uhdj9drV Any advices?
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