On 1/10/20 7:43 PM, Philip Brown wrote: > Surprisingly, a google search didnt seem to find the answer on this, so guess I should ask here: > > what determines if an rdb is "100% busy"? > > I have some backend OSDs, and an iSCSI gateway, serving out some RBDs. > > iostat on the gateway says rbd is 100% utilized > > iostat on individual OSds only goes as high as about 60% on a per-device basis. > CPU is idle. > Doesnt seem like network interface is capped either. > > So.. how do I improve RBD throughput? > The util is calculated based on average waits, see: https://coderwall.com/p/utc42q/understanding-iostat Just improving performance isn't just turning a knob and it will happen. It seems like your RBD can't flush it's I/O fast enough and that causes the iowait to go up. This can be all kinds of things: - Network (latency) - CPU on the OSDs Wido > > > -- > Philip Brown| Sr. Linux System Administrator | Medata, Inc. > 5 Peters Canyon Rd Suite 250 > Irvine CA 92606 > Office 714.918.1310| Fax 714.918.1325 > pbrown@xxxxxxxxxx| www.medata.com > _______________________________________________ > ceph-users mailing list > ceph-users@xxxxxxxxxxxxxx > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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