Thanks for the info everyone. On Dec 16, 2013 1:23 AM, "Kyle Bader" <kyle.ba...@gmail.com> wrote:
> >> Has anyone tried scaling a VMs io by adding additional disks and > >> striping them in the guest os? I am curious what effect this would have > >> on io performance? > > > Why would it? You can also change the stripe size of the RBD image. > Depending on the workload you might change it from 4MB to something like > 1MB or 32MB? That would give you more or less RADOS objects which will also > give you a different I/O pattern. > > The question comes up because it's common for people operating on EC2 to > stripe EBS volumes together for higher iops rates. I've tried striping > kernel RBD volumes before but hit some sort of thread limitation where > throughput was consistent despite the volume count. I've since learned the > thread limit is configurable. I don't think there is a thread limit that > needs to be tweaked for RBD via KVM/QEMU but I haven't tested this > empirically. As Wido mentioned, if you are operating your own cluster > configuring the stripe size may achieve similar results. Google used to use > a 64MB chunk size with GFS but switched to 1MB after they started > supporting more and more seek heavy workloads. > > _______________________________________________ > ceph-users mailing list > ceph-users@lists.ceph.com > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > >
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