Re: Fwd: High IOWait Issue

[ceph@xxxxxxxxxx]

I would Check with Tools like atop the utilization  of your Disks also. Perhaps something Related in dmesg or dorthin?

- Mehmet

Am 24. März 2018 08:17:44 MEZ schrieb Sam Huracan <nowitzki.sammy@xxxxxxxxx>:

Hi guys,

We are running a production OpenStack backend by Ceph.

At present, we are meeting an issue relating to high iowait in VM, in some MySQL VM, we see sometime IOwait reaches  abnormal high peaks which lead to slow queries increase, despite load is stable (we test with script simulate real load), you can see in graph.

https://prnt.sc/ivndni

MySQL VM are place on Ceph HDD Cluster, with 1 SSD journal for 7 HDD. In this cluster, IOwait on each ceph host is about 20%.

https://prnt.sc/ivne08

Can you guy help me find the root cause of this issue, and how to eliminate this high iowait?

Thanks in advance.

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