Re: [ceph-users] RBD+KVM problems with sequential read

2014-02-07 Thread Daniel Schwager
> I'm sorry, but I did not understand you :) Sorry (-: My finger touched the RETURN-key to fast... Try to setup a bigger value for the read ahead cache, maybe 256 MB? echo "262144">/sys/block/vda/queue/read_ahead_kb Try also "fio" performance tool - it will show more detailed information.

Re: [ceph-users] RBD+KVM problems with sequential read

2014-02-07 Thread Ирек Фасихов
-boun...@lists.ceph.com] *On Behalf Of * ??? > *Sent:* Friday, February 07, 2014 10:55 AM > *To:* Konrad Gutkowski > *Cc:* ceph-users@lists.ceph.com > *Subject:* Re: [ceph-users] RBD+KVM problems with sequential read > > > > echo "noop">/sys/block/vda/queue/scheduler >

Re: [ceph-users] RBD+KVM problems with sequential read

2014-02-07 Thread Daniel Schwager
: [ceph-users] RBD+KVM problems with sequential read 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

Re: [ceph-users] RBD+KVM problems with sequential read

2014-02-07 Thread Ирек Фасихов
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 200 bytes (20 GB) copied, 244.024 s, 82.0 MB/s Changing these param

Re: [ceph-users] RBD+KVM problems with sequential read

2014-02-07 Thread Konrad Gutkowski
Hi,W dniu 07.02.2014 o 08:14 Ирек Фасихов 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/vdaThanks.-- С уважением, Фасихов Ирек Нургаязов

[ceph-users] RBD+KVM problems with sequential read

2014-02-06 Thread Ирек Фасихов
Hi All. Hosts: Dell R815x5, 128 GB RAM, 25 OSD + 5 SSD(journal+system). Network: 2x10Gb+LACP Kernel: 2.6.32 QEMU emulator version 1.4.2, Copyright (c) 2003-2008 Fabrice Bellard POOLs: root@kvm05:~# ceph osd dump | grep 'rbd' pool 5 'rbd' rep size 2 min_size 1 crush_ruleset 2 object_hash rjenkins