From mboxrd@z Thu Jan 1 00:00:00 1970 From: John Hughes Subject: Re: MD performance options: More =?windows-1252?Q?CPU=92s_or_?= =?windows-1252?Q?more_Hz=92s=3F?= Date: Wed, 04 Nov 2009 15:39:18 +0100 Message-ID: <4AF19216.30300@Calva.COM> References: <66781b10911040149q165edf1s94a86f179f9af9fc@mail.gmail.com> <4AF18A39.6010404@tmr.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4AF18A39.6010404@tmr.com> Sender: linux-raid-owner@vger.kernel.org To: Bill Davidsen Cc: mark delfman , Linux RAID Mailing List List-Id: linux-raid.ids Bill Davidsen wrote: > mark delfman wrote: >> Hi... I am wondering if anyone can offer some advice on MD performance >> related to CPU (speed and or cores). > > You didn't ask: if you use ext[34] filesystems, there is a gain to be > had from tuning the stripe and stride parameters, at least for large > sequential io. My measurements were on 2.6.26, so are out of date, but > less head motion is always better. An external journal can be a huge win for ext3 if you are doing lots of file creates/deletes. (Striped raid, i.e. raid0/raid5/raid6/raid10 doesn't help the journal much as it is used sequentially. In my tests putting the journal on a raid1 and the rest of the fs on a raid10 makes things go much faster. If you have enough disks of course :-))