[Lustre-discuss] (no subject)

[Andreas Dilger]

On Mar 06, 2009  09:37 -0800, Evan Felix wrote:
> Sebastion, you are correct on the OST Memory, you probably wont need the
> 16GB, and if you can save money on using only 4GB, and buy bigger/more
> drives, you will probably be better off.

In the 1.8 release the OSS nodes will cache reads with little/no performance
impact even if your app doesn't use them, but of course performance
improvement if you app DOES re-read files commonly, so that should be taken
into account.

> On 3/5/09 6:29 PM, "Sebastian Gutierrez"
> <sebastian.gutierrez at cs.stanford.edu> wrote:
> 
> > Hello
> > 
> > I am looking for advice or suggestions on specking the MDS and OSS for a
> > new file system I am building.
> > 
> > The IO patterns as have been explained to me are jobs that either create a
> > big mpeg file or thousands of about 100kb frames for video.
> > This could grow to hudreds of thousands of 100k files.
> > 
> > I have specked
> > 2 MDS for a cluster
> > 8x300GB SAS 15k drives for the MDT in a raid 10(I used raid 10 to reduce
> > the chance of the MDT becomming a bottleneck with many small files)
> > 2x300GB SAS 15k drives for the MGS in a raid 1

The MGS needs virtually no disk IO, so using smallest/cheapest SATA drives
is fine.

> > 4 OSS servers
> > 16GB 667mhz ram
> > 2.5 ghz dual quad core procs
> > 6x1TB SATA 3 7.2k disks 5TB OST in a raid 5 (possibly running software raid)
> > expandable to 2 5TB OSTs Per OSS
> > 1xHotspare
> > 
> > Since this is the first Lustre file system I am building.  I noticed the
> > sizing page:
> > http://manual.lustre.org/manual/LustreManual16_HTML/SystemLimits.html#50548887
> > _46859
> > 
> > The document mentions only dual core procs in regards to the MDS.

That's because this section is old.  If you want more MDS performance (up
to a limit) adding more cores + RAM is useful.

> > The document also mentions a much lower amount of system RAM required for
> > the OST.
> > 
> > Am I wasting resources here by over-specking these boxes or is it a good
> > idea to over spec a bit?
> > 
> > Am I on the right track based on the IO pattern as I understand it?
> > 
> > Sebastian
> > 
> > _______________________________________________
> > Lustre-discuss mailing list
> > Lustre-discuss at lists.lustre.org
> > http://lists.lustre.org/mailman/listinfo/lustre-discuss
> 
> _______________________________________________
> Lustre-discuss mailing list
> Lustre-discuss at lists.lustre.org
> http://lists.lustre.org/mailman/listinfo/lustre-discuss

Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.