>> In our small test deployments (160 HDs and OSDs across 20 machines) >> our performance is quickly bounded by CPU and memory overhead. These >> are 2U machines with 2x 6-core Nehalem; and running 8 OSDs consumed >> 25% of the total CPU time. This was a cuttlefish deployment. > >You might be interested in trying a more recent release. We've implemented >the SSE4 CRC32c instruction for CPUs that support it, which dramatically >reduces CPU overhead during large sequential writes. On a 4U box with 24 >spinning disks and 8 SSDs (4 bay unused) this brought CPU usage down from >something like 80% to around 40% during large sequential writes if I'm >remembering correctly. The choice of the underlying filesystem will also >affect CPU overhead. BTRFS tends to be a bit more CPU intensive than say >EXT4. > Mark, what type of CPUs are in the 4U box (number of sockets, architecture, core count, frequency)? _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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