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The general rule is: Ceph is an SDS. With Ceph it’s hard to achieve random read latencies less than 0.5ms and random write latencies less than 1ms, ''no matter what drives or network you use''. This stands for only 2000 iops random read and 1000 iops random write, and even this result is good if you manage to achieve it. With BIS hardware and some tuning you may be able to improve it, but only twice or so.
There is Nick Fisk’s presentation titled «Low-latency Ceph». By «low-latency» he only means 0.7ms, which is only ~1500 iops.
=== Test your disks ===
