Open Stack

Hello, all.

   We have measured disk I/O performance on openstack virtual machines
with aid of
FIO tool. We've tested performance on root dist drive device, test
consists of write operationby 4kb
blocks to file with size 90Gb (prefilled in advance).
    We use qcow2 image for vm, ephemeral drive and virtio driver.
All configuration goes in attachment.

      There are some results:

test 1

threads 1, 5, 10, 15, 20, 40
iops     72,58,49,60,94,72

test 2
threads 1, 5, 10, 15, 20, 40
iops     71,60,54,88,52,52

test 3
threads 1, 5, 10, 15, 20, 40
iops     71,49,58,51,128,130

test 4
threads 1, 5, 10, 15, 20, 40
iops     65,49,60,56,52,63

As it is shown performance degraded during increasing amount of
threads, also deviation of results on 40 threads is very big.
     Have you any ideas how to explain performance behaviour?

Kind regards, Gleb Stepanov.
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