Re: RBD+KVM problems with sequential read

[Ирек Фасихов <malmyzh@xxxxxxxxx>]

echo "noop">/sys/block/vda/queue/scheduler 

echo "1000" >/sys/block/vda/queue/nr_requests

echo "8192">/sys/block/vda/queue/read_ahead_kb

[root@nfs tmp]# dd if=test of=/dev/null

39062500+0 records in

39062500+0 records out

20000000000 bytes (20 GB) copied, 244.024 s, 82.0 MB/s

Changing these parameters are not affected...

Are there other ideas on this problem? 

Thank you.

2014-02-07 Konrad Gutkowski <konrad.gutkowski@xxxxxx>:

Hi,

W dniu 07.02.2014 o 08:14 Ирек Фасихов <malmyzh@xxxxxxxxx> pisze:

[...]

Why might such a low speed sequential read? Do ideas on this issue?

Iirc you need to set your readahead for the device higher (inside the vm) to compensate for network rtt.

blockdev --setra x /dev/vda

Thanks.

-- 

С уважением, Фасихов Ирек Нургаязович

Моб.: +79229045757

Regards,

Konrad Gutkowski

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--

С уважением, Фасихов Ирек Нургаязович

Моб.: +79229045757

_______________________________________________
ceph-users mailing list
ceph-users@xxxxxxxxxxxxxx
http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com