[Gluster-users] gluster "a bit" slower - was Re: gluster local vs local = gluster x4 slower

[Jeremy Enos]

I did supply more context than you mention- it was a tar file of X MB w/ 
Y files, and compares to disk w/ cache or w/o cache by Z seconds.  This 
should give some idea of the task I was attempting and even a basis for 
replication of the test.

     Jeremy

On 3/23/2010 12:37 PM, Ian Rogers wrote:
>
> It's not very helpful to say gluster is "x4" slower though as it all 
> depends on overhead and context.
>
> In our setup we've found PHP pages (with lots of includes) load around 
> 100ms slower - which ranges from x2 down to just 10% slower depending 
> on what else is going on...
>
> It'd be interesting to know what the fuse overhead is. If gluster had 
> some resource available it would be really cool to see how the 
> overhead reduced if gluster was a kernel module rather than userspace 
> fuse....
>
> As always YMMV.
>
> Ian
>
> On 23/03/2010 11:02, Stephan von Krawczynski wrote:
>> On Tue, 23 Mar 2010 02:59:35 -0600 (CST)
>> "Tejas N. Bhise"<tejas at gluster.com>  wrote:
>>
>>> Out of curiosity, if you want to do stuff only on one machine,
>>> why do you want to use a distributed, multi node, clustered,
>>> file system ?
>> Because what he does is a very good way to show the overhead produced 
>> only by
>> glusterfs and nothing else (i.e. no network involved).
>> A pretty relevant test scenario I would say.
>>
>> -- 
>> Regards,
>> Stephan
>>
>>
>>> Am I missing something here ?
>>>
>>> Regards,
>>> Tejas.
>>>
>>> ----- Original Message -----
>>> From: "Jeremy Enos"<jenos at ncsa.uiuc.edu>
>>> To: gluster-users at gluster.org
>>> Sent: Tuesday, March 23, 2010 2:07:06 PM GMT +05:30 Chennai, 
>>> Kolkata, Mumbai, New Delhi
>>> Subject: [Gluster-users] gluster local vs local = gluster x4 slower
>>>
>>> This test is pretty easy to replicate anywhere- only takes 1 disk, one
>>> machine, one tarball.  Untarring to local disk directly vs thru gluster
>>> is about 4.5x faster.  At first I thought this may be due to a slow 
>>> host
>>> (Opteron 2.4ghz).  But it's not- same configuration, on a much faster
>>> machine (dual 3.33ghz Xeon) yields the performance below.
>>>
>>> ####THIS TEST WAS TO A LOCAL DISK THRU GLUSTER####
>>> [root at ac33 jenos]# time tar xzf
>>> /scratch/jenos/intel/l_cproc_p_11.1.064_intel64.tgz
>>>
>>> real    0m41.290s
>>> user    0m14.246s
>>> sys     0m2.957s
>>>
>>> ####THIS TEST WAS TO A LOCAL DISK (BYPASS GLUSTER)####
>>> [root at ac33 jenos]# cd /export/jenos/
>>> [root at ac33 jenos]# time tar xzf
>>> /scratch/jenos/intel/l_cproc_p_11.1.064_intel64.tgz
>>>
>>> real    0m8.983s
>>> user    0m6.857s
>>> sys     0m1.844s
>>>
>>> ####THESE ARE TEST FILE DETAILS####
>>> [root at ac33 jenos]# tar tzvf
>>> /scratch/jenos/intel/l_cproc_p_11.1.064_intel64.tgz  |wc -l
>>> 109
>>> [root at ac33 jenos]# ls -l
>>> /scratch/jenos/intel/l_cproc_p_11.1.064_intel64.tgz
>>> -rw-r--r-- 1 jenos ac 804385203 2010-02-07 06:32
>>> /scratch/jenos/intel/l_cproc_p_11.1.064_intel64.tgz
>>> [root at ac33 jenos]#
>>>
>>> These are the relevant performance options I'm using in my .vol file:
>>>
>>> #------------Performance Options-------------------
>>>
>>> volume readahead
>>>     type performance/read-ahead
>>>     option page-count 4           # 2 is default option
>>>     option force-atime-update off # default is off
>>>     subvolumes ghome
>>> end-volume
>>>
>>> volume writebehind
>>>     type performance/write-behind
>>>     option cache-size 1MB
>>>     subvolumes readahead
>>> end-volume
>>>
>>> volume cache
>>>     type performance/io-cache
>>>     option cache-size 1GB
>>>     subvolumes writebehind
>>> end-volume
>>>
>>> What can I do to improve gluster's performance?
>>>
>>>       Jeremy
>>>
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>>
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