On Sep 27, 2010, at 8:16 PM, Tom Bishop <bisho...@gmail.com> wrote:

> Here are the iostats:
> 
> 
> Device:         rrqm/s   wrqm/s   r/s   w/s   rsec/s   wsec/s avgrq-sz 
> avgqu-sz   await  svctm  %util
> sda               0.15     2.47  0.41  0.82    13.01    26.36    31.97     
> 0.01    6.98   1.01   0.12
> sda1              0.02     0.00  0.00  0.00     0.04     0.00    24.50     
> 0.00    5.38   4.82   0.00
> sda2              0.01     0.00  0.00  0.00     0.03     0.00    37.79     
> 0.00    6.77   5.85   0.00
> sda3              0.12     2.47  0.40  0.82    12.93    26.36    31.98     
> 0.01    6.96   1.01   0.12
> sdb               1.48     0.00 315.21  0.01 40533.39     0.75   128.59    
> 26.94   85.45   2.80  88.24
> sdb1              1.47     0.00 315.21  0.01 40533.30     0.75   128.59    
> 26.94   85.45   2.80  88.24

Average queue size of 26.94 requests, average wait time of 85.45ms, service 
time of 2.8ms ain't bad, but means the sequential IO is randomizing and backing 
up the IO.

Chances are this is probably a 4k sector drive and the partition's alignment 
crosses a 4k page causing double reads. Better to start partitions on sector 
2048 instead of 63.

Am I correct on these?

If so I'd break the RAID re-partition and resilver it.

-Ross

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