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

[Ian Rogers]

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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