Hi Simon,
Have you tried using the Deadline scheduler on the Linux nodes? The deadline scheduler prioritises reads over writes. I believe it tries to service all reads within 500ms whilst writes can be delayed up to 5s. I don’t the exact effect Ceph will have over the top of this, but this would be the first thing I would try. Nick From: ceph-users [mailto:[email protected]] On Behalf Of Xu (Simon) Chen Sent: 31 October 2014 19:37 To: [email protected] Subject: [ceph-users] prioritizing reads over writes Hi all, My workload is mostly writes, but when the writes reach a certain throughput (iops wise not much higher) the read throughput would tank. This seems to be impacting my VMs' responsiveness overall. Reads would recover after write throughput drops. Is there any way to prioritize read over write, or at least guarantee a certain level of aggregated read throughput in a cluster? Thanks. -Simon
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