As a result of running this command, 'iostat -x -m 30 30'. I get the following output. sda and sdb are sata3 drives in a striped raid (0).
How do I interpret these results for a raid. Specifically,
a) await to svctm ratio is close to 1 for individual drives but > 2 for dm-x.
b) I expected to see rMB/s closer to 300 which is the SATA3 speed with the reasonable good disks I am using. But these are at 1.xx MB/s. What does thie mean?
c) What's the interpretation to monitor the raid performance? Seems like there is enough bandwidth for I/O here but when I bump up the processes just a notched, there is a long await to svctm ratio.
Thanks,
Madhav.
avg-cpu: %user %nice %system %iowait %steal %idle
33.62 0.00 6.90 0.02 0.00 59.45
Device: rrqm/s wrqm/s r/s w/s rMB/s wMB/s avgrq-sz avgqu-sz await svctm %util
sda 10.03 0.20 20.37 0.20 1.16 0.00 115.19 0.05 2.63 2.53 5.21
sdb 10.07 0.00 19.97 0.13 1.15 0.00 117.67 0.05 2.65 2.56 5.14
dm-0 0.00 0.00 41.93 0.47 2.31 0.00 111.60 0.12 2.88 1.35 5.70
dm-1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
dm-2 0.00 0.00 41.93 0.47 2.31 0.00 111.60 0.12 2.88 1.35 5.71
dm-3 0.00 0.00 41.93 0.40 2.31 0.00 111.77 0.12 2.89 1.35 5.71
dm-4 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
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