Hi,W dniu 07.02.2014 o 08:14 Ирек Фасихов malm...@gmail.com 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,
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 parameters
: [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+0 records out
200 bytes (20 GB) copied
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.
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
