We have a few of DBs which aren't using disk IO to optimum capacity.
They're running at a load of 1.5 or so with a high workload of pending
When I do iostat I'm not noticing much IO :
Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s rkB/s wkB/s
avgrq-sz avgqu-sz await svctm %util
sda 0.00 13.73 128.43 252.94 1027.45 1695.10 513.73
847.55 7.14 90.13 285.00 2.53 96.57
This is only seeing about 500k -> 1M per second throughput.
When I run bonnie++ on these drives they're showing 20M->40M throughput.
Which is really strange.
Most of our queries are single INSERTS/DELETES. I could probably
to become batch operations but I think I'd still end up seeing the above
results but with higher throughput.
... so I'd like to get to the bottom of this before moving forward?
I ran OPTIMIZE TABLE on all tables but nothing.
The boxes aren't paging.
They're running on a RAID5 disk on XFS.
Could it be that the disks are having to do a number of HEAD seeks since we
have large tables?
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