From mboxrd@z Thu Jan 1 00:00:00 1970 From: Justin Piszcz Subject: Re: below 10MB/s write on raid5 Date: Tue, 12 Jun 2007 13:14:55 -0400 (EDT) Message-ID: References: <200706111446.55813.Dexter.Filmore@gmx.de> <466ED4F6.5060204@tmr.com> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Return-path: In-Reply-To: <466ED4F6.5060204@tmr.com> Sender: linux-raid-owner@vger.kernel.org To: Bill Davidsen Cc: Dexter Filmore , linux-raid@vger.kernel.org List-Id: linux-raid.ids On Tue, 12 Jun 2007, Bill Davidsen wrote: > Dexter Filmore wrote: >> I recently upgraded my file server, yet I'm still unsatisfied with the >> write speed. >> Machine now is a Athlon64 3400+ (Socket 754) equipped with 1GB of RAM. >> The four RAID disks are attached to the board's onbaord sATA controller >> (Sil3114 attached via PCI) >> Kernel is 2.6.21.1, custom on Slackware 11.0. >> RAID is on four Samsung SpinPoint disks, has LVM, 3 volumes atop of each >> XFS. >> >> The machine does some other work, too, but still I would have suspected to >> get into the 20-30MB/s area. Too much asked for? >> > > Increase your stripe cache size in /sys/block/mdX/md/stripe_cache_size. If > you have a chunk size of 256, try setting the cache size to 8192 and see if > your write performance ends up ~100MB/s or so. > > echo 8192 > /sys/block/mdX/md/stripe_cache_size > > Where "X" is your array name, of course. > > Note, larger values will help more, but it's definitely diminishing returns, > so don't get carried away. There was a report of problems with size > 32768, > I don't remember the details, so I would avoid that as well. > > -- > bill davidsen > CTO TMR Associates, Inc > Doing interesting things with small computers since 1979 > > - > To unsubscribe from this list: send the line "unsubscribe linux-raid" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > I was the one who tried > 32768 it crashed the machine (on an older box). Justin.