Hello,
Lately I was trying to get KVM to perform well on RBD. But it still
appears elusive.
[root@alpha etc]# rados -p rbd bench 120 seq -t 8
Total time run: 16.873277
Total reads made: 302
Read size: 4194304
Bandwidth (MB/sec): 71.592
Average Latency: 0.437984
Max latency: 3.26817
Min latency: 0.015786
Fairly good performance. But when I run in KVM:
[root@mail ~]# hdparm -tT /dev/vda
/dev/vda:
Timing cached reads: 8808 MB in 2.00 seconds = 4411.49 MB/sec
Timing buffered disk reads: 10 MB in 6.21 seconds = 1.61 MB/sec
Not even close to what rados bench show! I even seen 900KB/sec
performance. Such slow read performance of course affecting guests.
Any ideas where to start to look for performance boost?
Regards,
Vladimir
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