[Gluster-users] Performance

Mohit Anchlia mohitanchlia at gmail.com
Tue May 3 18:44:03 UTC 2011

Does anyone know if new controller cards can be replaced without
re-installing OS?

On Wed, Apr 27, 2011 at 11:59 AM, Burnash, James <jburnash at knight.com> wrote:
> We use HP controllers here - p800, p812. They're pretty good - but I believe they're fairly pricey (my sources say $600-$800 for the p812, depending on the options for battery and cache.
> I use these controllers on my Gluster backend storage servers. Then again, we're an HP shop.
> James Burnash, Unix Engineering
> -----Original Message-----
> From: gluster-users-bounces at gluster.org [mailto:gluster-users-bounces at gluster.org] On Behalf Of Mohit Anchlia
> Sent: Wednesday, April 27, 2011 2:47 PM
> To: landman at scalableinformatics.com
> Cc: gluster-users at gluster.org
> Subject: Re: [Gluster-users] Performance
> What are some of the good controller cards would you recommend for SAS
> drives? Dell and Areca is what I am seeing most suggested online.
> On Tue, Apr 26, 2011 at 4:43 PM, Mohit Anchlia <mohitanchlia at gmail.com> wrote:
>> In your experience does it really help having journal on different
>> disk? Just trying to see if it's worth the effort. Also, Gluster also
>> recommends creating mkfs with larger blocks mkfs -I 256
>> As always thanks for the suggestion.
>> On Tue, Apr 26, 2011 at 4:31 PM, Joe Landman
>> <landman at scalableinformatics.com> wrote:
>>> On 04/26/2011 05:48 PM, Mohit Anchlia wrote:
>>>> I am not sure how valid this performance url is
>>>> http://www.gluster.com/community/documentation/index.php/Guide_to_Optimizing_GlusterFS
>>>> Does it make sense to separate out the journal and create mkfs -I 256?
>>>> Also, if I already have a file system on a different partition can I
>>>> still use it to store journal from other partition without corrupting
>>>> the file system?
>>> Journals are small write heavy.  You really want a raw device for them.  You
>>> do not want file system caching underneath them.
>>> Raw partition for an external journal is best.  Also, understand that ext*
>>> suffers badly under intense parallel loads.  Keep that in mind as you make
>>> your file system choice.
>>>> On Thu, Apr 21, 2011 at 7:23 PM, Joe Landman
>>>> <landman at scalableinformatics.com>  wrote:
>>>>> On 04/21/2011 08:49 PM, Mohit Anchlia wrote:
>>>>>> After lot of digging today finaly figured out that it's not really
>>>>>> using PERC controller but some Fusion MPT. Then it wasn't clear which
>>>>> PERC is a rebadged LSI based on the 1068E chip.
>>>>>> tool it supports. Finally I installed lsiutil and was able to change
>>>>>> the cache size.
>>>>>> [root at dsdb1 ~]# lspci|grep LSI
>>>>>> 02:00.0 SCSI storage controller: LSI Logic / Symbios Logic SAS1068E
>>>>>> PCI-Express Fusion-MPT SAS (rev 08)
>>>>>  This looks like PERC.  These are roughly equivalent to the LSI 3081
>>>>> series.
>>>>>  These are not fast units.  There is a variant of this that does RAID6,
>>>>> its
>>>>> usually available as a software update or plugin module (button?) to
>>>>> this.
>>>>>  I might be thinking of the 1078 chip though.
>>>>>  Regardless, these are fairly old designs.
>>>>>> [root at dsdb1 ~]# dd if=/dev/zero of=/data/big.file bs=128k count=40k
>>>>>> oflag=direct
>>>>>> 1024+0 records in
>>>>>> 1024+0 records out
>>>>>> 134217728 bytes (134 MB) copied, 0.742517 seconds, 181 MB/s
>>>>>> I compared this with SW RAID mdadm that I created yesterday on one of
>>>>>> the servers and I get around 300MB/s. I will test out first with what
>>>>>> we have before destroying and testing with mdadm.
>>>>> So the software RAID is giving you 300 MB/s and the hardware 'RAID' is
>>>>> giving you ~181 MB/s?  Seems a pretty simple choice :)
>>>>> BTW: The 300MB/s could also be a limitation of the PCIe channel
>>>>> interconnect
>>>>> (or worse, if they hung the chip off a PCIx bridge).  The motherboard
>>>>> vendors are generally loathe to put more than a few PCIe lanes for
>>>>> handling
>>>>> SATA, Networking, etc.  So typically you wind up with very low powered
>>>>> 'RAID' and 'SATA/SAS' on the motherboard, connected by PCIe x2 or x4 at
>>>>> most.  A number of motherboards have NICs that are served by a single
>>>>> PCIe
>>>>> x1 link.
>>>>>> Thanks for your help that led me to this path. Another question I had
>>>>>> was when creating mdadm RAID does it make sense to use multipathing?
>>>>> Well, for a shared backend over a fabric, I'd say possibly.  For an
>>>>> internal
>>>>> connected set, I'd say no.  Given what you are doing with Gluster, I'd
>>>>> say
>>>>> that the additional expense/pain of setting up a multipath scenario
>>>>> probably
>>>>> isn't worth it.
>>>>> Gluster lets you get many of these benefits at a higher level in the
>>>>> stack.
>>>>>  Which to a degree, and in some use cases, obviates the need for
>>>>> multipathing at a lower level.  I'd still suggest real RAID at the lower
>>>>> level (RAID6, and sometimes RAID10 make the most sense) for the backing
>>>>> store.
>>>>> --
>>>>> 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
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