gstripe performance scaling with many disks

[Ivan Voras]

R. B. Riddick wrote:
> --- Ivan Voras <ivoras at fer.hr> wrote:
>> Vasil Dimov wrote:
>>> 17 drives:
>>> dT: 0.563s  w: 0.500s
>>>  L(q)  ops/s    r/s   kBps   ms/r    w/s   kBps   ms/w   %busy Name
>>>     5    185    178    848   18.9      0      0    0.0   88.8| ggate100
>> Ok, so ops/s is increasing but it's not conclusive. Does anyone know how
>> to get KB/t stats for synthetic geom devices?
>>
> I would say:
> transaction size = (volume per second) / (operations per second)
> E. g.:
> 848KBps/(178r/s) = 4.76KB/op
> or
> 1028KBps/(116r/s) = 8.86KB/op

Well "doh", nowadays I don't know how to calculate anymore :)

Hmmm, it's strange - it's 2x lower than it should be. For 8 drives, each
should do 16 KB/s but they do 8 KB/s. Maybe something's chopping the
requests at 64 KB each?



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