[Gluster-users] Performance

[Mohit Anchlia]

Hi Joe,

When you get chance can you please at my mail? It will be helpful to
get your advise.


On Wed, Apr 20, 2011 at 6:16 PM, Mohit Anchlia <mohitanchlia at gmail.com> wrote:
> Yes indeed. As soon as I sent you last email I realized that and set
> the write back option. Now I get 130MB/s better but still nowhere
> close to 600MB/s as advertised or what others say one should see.
>
> What are your recommendations about HW choice? What is more
> preferrable and better?
>
> Another question do I need to set WCE on all the disks first before
> creating RAID0? Or can I do that after creating RAID0? I tried to set
> WCE on existing RAID0 but it fails "change_mode_page: failed fetching
> page: Caching (SBC)".
>
>  sdparm --set=WCE --save /dev/sda
>    /dev/sda: FUJITSU   MBD2300RC         D809
>
> dd if=/dev/zero of=/dev/sda bs=128k count=80k oflag=direct
> 81920+0 records in
> 81920+0 records out
> 10737418240 bytes (11 GB) copied, 82.8041 seconds, 130 MB/s
>
> Thanks for your help as always.
>
> On Wed, Apr 20, 2011 at 5:53 PM, Joe Landman
> <landman at scalableinformatics.com> wrote:
>> On 04/20/2011 07:50 PM, Mohit Anchlia wrote:
>>>
>>> I did that but it looks the same. I did get an error even though it
>>> says write-caching is on.
>>>
>>> [root at dslg1 ~]# hdparm -W1 /dev/sda
>>>
>>> /dev/sda:
>>>  setting drive write-caching to 1 (on)
>>>  HDIO_DRIVE_CMD(setcache) failed: Invalid argument
>>> [root at dslg1 ~]# hdparm /dev/sda
>>
>> You might need sdparm
>>
>>        sdparm -a /dev/sda | grep WCE
>>
>> With WCE on I see
>>
>>        [root at smash ~]# sdparm -a /dev/sda | grep WCE
>>          WCE         1
>>
>> and with it off, I see
>>
>>        [root at smash ~]# hdparm -W0 /dev/sda
>>
>>        /dev/sda:
>>         setting drive write-caching to 0 (off)
>>         write-caching =  0 (off)
>>
>>        [root at smash ~]# sdparm -a /dev/sda | grep WCE
>>          WCE         0
>>
>> You might need to change WCE using
>>
>>        sdparm --set=WCE -a /dev/sda
>>
>> or similar ...
>>
>>>
>>> /dev/sda:
>>>  readonly     =  0 (off)
>>>  readahead    = 256 (on)
>>>  geometry     = 36472/255/63, sectors = 585937500, start = 0
>>> [root at dslg1 ~]# [A
>>> [root at dslg1 ~]# dd if=/dev/zero of=/dev/sda bs=128k count=1k oflag=direct
>>> 1024+0 records in
>>> 1024+0 records out
>>> 134217728 bytes (134 MB) copied, 8.10005 seconds, 16.6 MB/s
>>>
>>>
>>> On Wed, Apr 20, 2011 at 5:45 PM, Joe Landman
>>> <landman at scalableinformatics.com>  wrote:
>>>>
>>>> On 04/20/2011 07:28 PM, Mohit Anchlia wrote:
>>>>>
>>>>> dd of=/dev/null if=/dev/sda bs=128k count=80k iflag=direct
>>>>> 81920+0 records in
>>>>> 81920+0 records out
>>>>> 10737418240 bytes (11 GB) copied, 83.8293 seconds, 128 MB/s
>>>>
>>>> Ok, this is closer to what I was expecting (really ~150 MB/s would make
>>>> more
>>>> sense to me, but I can live with 128 MB/s).
>>>>
>>>> The write speed is definitely problematic.  I am wondering if write cache
>>>> is
>>>> off, and other features are turned off in strange ways.
>>>>
>>>> This is a 2 year old SATA disk
>>>>
>>>> [root at smash ~]# dd if=/dev/zero of=/dev/sda2 bs=128k oflag=direct
>>>> dd: writing `/dev/sda2': No space left on device
>>>> 16379+0 records in
>>>> 16378+0 records out
>>>> 2146798080 bytes (2.1 GB) copied, 20.8322 s, 103 MB/s
>>>>
>>>> Write cache is enabled.  Turning write cache off (might not be so
>>>> relevant
>>>> for a RAID0),
>>>>
>>>> [root at smash ~]# hdparm -W /dev/sda
>>>>
>>>> /dev/sda:
>>>>  write-caching =  1 (on)
>>>> [root at smash ~]# hdparm -W0 /dev/sda
>>>>
>>>> /dev/sda:
>>>>  setting drive write-caching to 0 (off)
>>>>  write-caching =  0 (off)
>>>>
>>>> [root at smash ~]# dd if=/dev/zero of=/dev/sda2 bs=128k oflag=direct
>>>> dd: writing `/dev/sda2': No space left on device
>>>> 16379+0 records in
>>>> 16378+0 records out
>>>> 2146798080 bytes (2.1 GB) copied, 155.636 s, 13.8 MB/s
>>>>
>>>> See if you can do an
>>>>
>>>>        hdparm -W1 /dev/sda
>>>>
>>>> and see if it has any impact on the write speed.  If you are using a
>>>> RAID0,
>>>> safety isn't so much on your mind anyway, so you can see if you can
>>>> adjust
>>>> your cache settings.  If this doesn't work, you might need to get to the
>>>> console and tell it to allow caching.
>>>>
>>>>
>>>> --
>>>> Joseph Landman, Ph.D
>>>> Founder and CEO
>>>> Scalable Informatics, Inc.
>>>> email: landman at scalableinformatics.com
>>>> web  : http://scalableinformatics.com
>>>>       http://scalableinformatics.com/sicluster
>>>> phone: +1 734 786 8423 x121
>>>> fax  : +1 866 888 3112
>>>> cell : +1 734 612 4615
>>>>
>>
>>
>> --
>> Joseph Landman, Ph.D
>> Founder and CEO
>> Scalable Informatics, Inc.
>> email: landman at scalableinformatics.com
>> web  : http://scalableinformatics.com
>>       http://scalableinformatics.com/sicluster
>> phone: +1 734 786 8423 x121
>> fax  : +1 866 888 3112
>> cell : +1 734 612 4615
>>
>