Re: libvirt qemu/kvm/rbd inside VM read slow

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



ceph osd dump, please.

10 янв. 2014 г. 18:29 пользователь "Steffen Thorhauer" <steffen.thorhauer@xxxxxxxxxxxxxxxxxxxxxxx> написал:
On 01/10/2014 02:35 PM, Wido den Hollander wrote:




Op 10 jan. 2014 om 18:49 heeft "Steffen Thorhauer" <steffen.thorhauer@xxxxxxxxxxxxxxxxxxxxxxx> het volgende geschreven:

On 01/10/2014 01:21 PM, Ирек Фасихов wrote:
You need to use VirtIO.

   <target dev='vdb' bus='virtio'/>


with this parameter ist not a real performance increase:
 dd if=/dev/zero of=zerofile-2 bs=1G count=8
8+0 records in
8+0 records out
8589934592 bytes (8.6 GB) copied, 73.8425 s, 116 MB/s

and reading:

trompete@multius:~$ dd if=zerofile-2 of=/dev/null bs=1G count=8
8+0 records in
8+0 records out
8589934592 bytes (8.6 GB) copied, 429.528 s, 20.0 MB/s


What happens if you increase the read_ahead_kb value for the device to 4096k. That is inside the guest.


cat read_ahead_kb
65536

trompete@multius:~$ dd if=zerofile-2 of=/dev/null bs=1G count=8
8+0 records in
8+0 records out
8589934592 bytes (8.6 GB) copied, 382.148 s, 22.5 MB/s


-- 
______________________________________________________________________
Steffen Thorhauer

Department of Technichal and Business Information Systems (ITI)
Faculty of Computer Science (FIN)
  Otto von Guericke University Magdeburg
Universitaetsplatz 2
39106 Magdeburg, Germany

phone: 0391 67 52996
fax: 0391 67 12341
email: sth@xxxxxxxxxxxxxxxxxxxxxxx
url: http://wwwiti.cs.uni-magdeburg.de/~thorhaue        
_______________________________________________
ceph-users mailing list
ceph-users@xxxxxxxxxxxxxx
http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com

[Index of Archives]     [Information on CEPH]     [Linux Filesystem Development]     [Ceph Development]     [Ceph Large]     [Ceph Dev]     [Linux USB Development]     [Video for Linux]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]     [xfs]


  Powered by Linux