Christian, Excellent performance improvements base on your guide, I set so small rbd cache size before, so do not get any improvements using RBD cache. Thanks a lot! Jian Li At 2014-07-08 10:14:27, "Christian Balzer" <chibi at gol.com> wrote: > >Hello, > >how did you come up with those bizarre cache sizes? > >Either way, if you test with FIO anything that will significantly exceed >the size of the cache will have very little to no effect. > >To verify things, set the cache values to be based around 2GB and test >with a FIO that is just 1GB in size. >This will also increase the memory footprint of your VM (if you run enough >tests) to that of its memory limits PLUS the cache, verifying that the >cache is actually on. > >RBD caching works well with the default sizes for small, bursty IOs. > >Christian > >On Tue, 8 Jul 2014 21:08:49 +0800 (CST) lijian wrote: > >> Haomai Wang, >> >> I use the FIO to test 4K and 1M read/write under iodepth=1 and >> iodepth=32 in VM Do you know the improvements percentage using cache >> base on yourself test. >> >> Thanks! >> JIan Li >> >> At 2014-07-08 08:47:39, "Haomai Wang" <haomaiwang at gmail.com> wrote: >> >With info you provided, I think you have enabled rbd cache. As for >> >performance improvement, it's related to your performance tests >> > >> >On Tue, Jul 8, 2014 at 8:34 PM, lijian <blacker1981 at 163.com> wrote: >> >> Hello, >> >> >> >> I want to enable the qemu rbd writeback cache, the following is the >> >> settings in /etc/ceph/ceph.conf >> >> [client] >> >> rbd_cache = true >> >> rbd_cache_writethrough_until_flush = false >> >> rbd_cache_size = 27180800 >> >> rbd_cache_max_dirty = 20918080 >> >> rbd_cache_target_dirty = 16808000 >> >> rbd_cache_max_dirty_age = 60 >> >> >> >> and the next section is the vm definition xml: >> >> <disk type='network' device='disk'> >> >> <driver name='qemu' cache='writeback'/> >> >> <auth username='estack'> >> >> <secret type='ceph' >> >> uuid='101ae7dc-bd59-485e-acba-efc8ddbe0d01'/> </auth> >> >> <source protocol='rbd' name='estack/new-libvirt-image'> >> >> <host name='X.X.X.X' port='6789'/> >> >> </source> >> >> <target dev='vdb' bus='virtio'/> >> >> <address type='pci' domain='0x0000' bus='0x00' slot='0x07' >> >> function='0x0'/> >> >> </disk> >> >> >> >> my host OS is Ubuntu, kernel 3.11.0-12-generic, the kvm-qemu is >> >> 1.5.0+dfsg-3ubuntu5.4, the guest os is Ubuntu 13.11 >> >> ceph version is 0.80.1 (a38fe1169b6d2ac98b427334c12d7cf81f809b74) >> >> >> >> no performance improvements using the above cache settings, So what's >> >> wrong with me, please help, thanks! >> >> >> >> Jian Li >> >> >> >> >> >> >> >> _______________________________________________ >> >> ceph-users mailing list >> >> ceph-users at lists.ceph.com >> >> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com >> >> >> > >> > >> > >> >-- >> >Best Regards, >> > >> >Wheat > > >-- >Christian Balzer Network/Systems Engineer >chibi at gol.com Global OnLine Japan/Fusion Communications >http://www.gol.com/ >_______________________________________________ >ceph-users mailing list >ceph-users at lists.ceph.com >http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.ceph.com/pipermail/ceph-users-ceph.com/attachments/20140709/2da8566c/attachment.htm>
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