Re: I/O Speed Comparisons

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

 



also during writes.
I've tested it now on linux with a virtio disk-drive:

    <disk type='network' device='disk'>
      <driver name='qemu' type='raw'/>
      <source protocol='rbd' name='rd/backup:rbd_cache=1'>
        <host name='rd-c2.ceph' port='6789'/>
        <host name='rd-c1.ceph' port='6789'/>
        <host name='wag-c1.ceph' port='6789'/>
      </source>
      <target dev='vda' bus='virtio'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x06'
function='0x0'/>
    </disk>

virsh console to the running VM.
Next - Write Test:
dd if=/dev/zero of=/bigfile bs=2M &

Serial console gets jerky, VM gets unresponsive. It doesn't crash, but
it's not 'healthy' either. CPU load isn't very high, it's in the waiting
state a lot:

Cpu(s):  0.0%us,  4.7%sy,  0.0%ni, 26.1%id, 68.4%wa,  0.0%hi,  0.3%si,
0.5%st
 1170 root      20   0 11736 2452  556 D  8.5  0.5   0:00.80 dd


Wolfgang

On 03/11/2013 01:42 PM, Mark Nelson wrote:
> I guess first question is does the jerky mouse behavior only happen
> during reads or writes too?  How is the CPU utilization in each case?
> 
> Mark
> 
> On 03/11/2013 01:30 AM, Wolfgang Hennerbichler wrote:
>> Let me know if I can help out with testing somehow.
>>
>> Wolfgang
>> ________________________________________
>> Von: ceph-users-bounces@xxxxxxxxxxxxxx
>> [ceph-users-bounces@xxxxxxxxxxxxxx]&quot; im Auftrag von &quot;Mark
>> Nelson [mark.nelson@xxxxxxxxxxx]
>> Gesendet: Samstag, 09. März 2013 20:33
>> Bis: ceph-users@xxxxxxxxxxxxxx
>> Betreff: Re:  I/O Speed Comparisons
>>
>> Thanks for all of this feedback guys!  It gives us some good data to try
>> to replicate on our end.  Hopefully I'll have some time next week to
>> take a look.
>>
>> Thanks!
>> Mark
>>
>> On 03/09/2013 08:14 AM, Erdem Agaoglu wrote:
>>> Mark,
>>>
>>> If it's any help, we've done a small totally unreliable benchmark on our
>>> end. For a KVM instance, we had:
>>> 260MB/s write, 200MB/s read on local SAS disks, attached as LVM LVs,
>>> 250MB/s write, 90MB/s read on RBD, 32 osds, all SATA.
>>>
>>> All sequential, a 10G network. It's more than enough currently but we'd
>>> like to improve RBD read performance.
>>>
>>> Cheers,
>>>
>>>
>>> On Sat, Mar 9, 2013 at 7:27 AM, Andrew Thrift <andrew@xxxxxxxxxxxxxxxxx
>>> <mailto:andrew@xxxxxxxxxxxxxxxxx>> wrote:
>>>
>>>      Mark,
>>>
>>>
>>>      I would just like to add, we too are seeing the same behavior with
>>>      QEMU/KVM/RBD.  Maybe it is a common symptom of high IO with this
>>> setup.
>>>
>>>
>>>
>>>      Regards,
>>>
>>>
>>>
>>>
>>>
>>>      Andrew
>>>
>>>
>>>      On 3/8/2013 12:46 AM, Mark Nelson wrote:
>>>
>>>          On 03/07/2013 05:10 AM, Wolfgang Hennerbichler wrote:
>>>
>>>
>>>
>>>              On 03/06/2013 02:31 PM, Mark Nelson wrote:
>>>              t
>>>
>>>                  If you are doing sequential reads, you may benefit by
>>>                  increasing the
>>>                  read_ahead_kb value for each device in
>>>                  /sys/block/<device>/queue on the
>>>                  OSD hosts.
>>>
>>>
>>>              Thanks, that didn't really help. It seems the VM has to
>>>              handle too much
>>>              I/O, even the mouse-cursor is jerking over the screen when
>>>              connecting
>>>              via vnc. I guess this is the wrong list, but it has somehow
>>>              to do with
>>>              librbd in connection with kvm, as the same machine on LVM
>>>              works just ok.
>>>
>>>
>>>          Thanks for the heads up Wolfgang.  I'm going to be looking into
>>>          QEMU/KVM
>>>          RBD performance in the coming weeks so I'll try to watch out
>>> for
>>>          this
>>>          behaviour.
>>>
>>>
>>>              Wolfgang
>>>              _________________________________________________
>>>              ceph-users mailing list
>>>              ceph-users@xxxxxxxxxxxxxx
>>> <mailto:ceph-users@xxxxxxxxxxxxxx>
>>>              http://lists.ceph.com/__listinfo.cgi/ceph-users-ceph.__com
>>>              <http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com>
>>>
>>>
>>>
>>>      _________________________________________________
>>>      ceph-users mailing list
>>>      ceph-users@xxxxxxxxxxxxxx <mailto:ceph-users@xxxxxxxxxxxxxx>
>>>      http://lists.ceph.com/__listinfo.cgi/ceph-users-ceph.__com
>>>      <http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com>
>>>
>>>
>>>
>>>
>>> -- 
>>> erdem agaoglu
>>>
>>>
>>>
>>> _______________________________________________
>>> ceph-users mailing list
>>> ceph-users@xxxxxxxxxxxxxx
>>> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
>>
>>
>> -- 
>> Mark Nelson
>> Performance Engineer
>> Inktank
>> _______________________________________________
>> ceph-users mailing list
>> ceph-users@xxxxxxxxxxxxxx
>> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
>> _______________________________________________
>> ceph-users mailing list
>> ceph-users@xxxxxxxxxxxxxx
>> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
>>
> 
> _______________________________________________
> ceph-users mailing list
> ceph-users@xxxxxxxxxxxxxx
> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com


-- 
DI (FH) Wolfgang Hennerbichler
Software Development
Unit Advanced Computing Technologies
RISC Software GmbH
A company of the Johannes Kepler University Linz

IT-Center
Softwarepark 35
4232 Hagenberg
Austria

Phone: +43 7236 3343 245
Fax: +43 7236 3343 250
wolfgang.hennerbichler@xxxxxxxxxxxxxxxx
http://www.risc-software.at
_______________________________________________
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