[Gluster-devel] Full bore.

Chris Johnson johnson at nmr.mgh.harvard.edu
Fri Nov 16 12:58:23 UTC 2007

On Fri, 16 Nov 2007, Anand Avati wrote:

      Very simple iozone call

      iozone -aN -r 32k -s 131072k

Now what I probably should be doing is testing this against the actual
load, the real image processing code to be used.  Did look at io
caching.  That would possibly help if a number of jobs on the cluster 
were to crunch the same file at the same time.  If that were not the
case I'm not sure what io caching would give me.

      The config?  You can't get much simpler than this, maybe by
pulling the read-ahead and write-behind which weren't there

volume brick1
   type storage/posix
   option directory /home/sdm1

volume server
   type protocol/server
   subvolumes brick1
   option transport-type tcp/server     # For TCP/IP transport
#  option client-volume-filename /etc/glusterfs/glusterfs-client.vol
   option auth.ip.brick1.allow *

volume writebehind
   type performance/write-behind
   option aggregate-size 131072 # in bytes
   subvolumes brick1

volume readahead
   type performance/read-ahead
   option page-size 65536 ### in bytes
   option page-count 16 ### memory cache size is page-count x page-size per file
   subvolumes brick1 

>>       Performance is still way below NFS.  I have turned on
>> write-behind and read-ahead.  And with fuse it's a little faster. but
>> not significantly.
> What is your IO pattern? what are the tests you are running? what is your
> interconnect? NFS can provide really good re-read performance which you can
> get out of glusterfs using io-cache on the client side.
>      Can we have a discussion on whether I'm heading in the right
>> direction and what order things go in for the config files?
> Can you paste your config files on pastebin and link it and also tell us the
> kind of application/IOtests you are running?
> thanks,
> avati
> -- 
> It always takes longer than you expect, even when you take into account
> Hofstadter's Law.
> -- Hofstadter's Law

Chris Johnson               |Internet: johnson at nmr.mgh.harvard.edu
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