From mboxrd@z Thu Jan 1 00:00:00 1970 From: Roman Mamedov Subject: Re: How to boost performance Date: Thu, 17 Jun 2010 10:01:09 +0600 Message-ID: <20100617100109.32a20ffa@natsu> References: Mime-Version: 1.0 Content-Type: multipart/signed; micalg=PGP-SHA1; boundary="Sig_/vwK7yVKQoJVqCO62lcqunNZ"; protocol="application/pgp-signature" Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: aragonx@dcsnow.com Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids --Sig_/vwK7yVKQoJVqCO62lcqunNZ Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable On Wed, 16 Jun 2010 18:23:36 -0400 aragonx@dcsnow.com wrote: > Before I start spewing server information, my question is this. Is there > anything I can tweak to improve my performance? It seems that the server > is CPU bound when I am transferring large amounts of data to or from it.= =20 > Any suggestions will be considered. Faster processor, switching to RAID > 0, etc. I'm hoping there is something I can do with the RAID software > though. Maybe a different chunk size or different algorithm? Increasing stripe cache size from the default of 256 should help immensely. echo 16384 > /sys/block/md0/md/stripe_cache_size Be warned that this consumes (^that amount * 4096 * number of disks) bytes = of RAM. Some benchmarks:=20 http://peterkieser.com/2009/11/29/raid-mdraid-stripe_cache_size-vs-write-tr= ansfer/ On a related note -- Neil, are there plans to implement a stripe cache which would be shared between all RAID devices? I have two RAID5s in my system, a= nd when one has a lot of writes, the other is often idle (or vice versa), so t= hat array's stripe cache is just sitting there wasting memory. Would be nice to be able to have a shared pool of RAM for stripe-caching all the arrays and the active one(s) using it to the fullest. --=20 With respect, Roman --Sig_/vwK7yVKQoJVqCO62lcqunNZ Content-Type: application/pgp-signature; name=signature.asc Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (GNU/Linux) iEYEARECAAYFAkwZngUACgkQTLKSvz+PZwhzhQCglMmq/t7jmKkry/6/YE2iCdDd PFEAnA2pt8ZgXDSgoVLO4oGRfOnbpPaW =u/ut -----END PGP SIGNATURE----- --Sig_/vwK7yVKQoJVqCO62lcqunNZ--