From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stan Hoeppner Subject: Re: md RAID with enterprise-class SATA or SAS drives Date: Wed, 23 May 2012 20:18:06 -0500 Message-ID: <4FBD8C4E.5090507@hardwarefreak.com> References: <4FAAE8F1.8000600@pocock.com.au> <4FABC7C6.4030107@turmel.org> <4FAC2FF2.5060305@hardwarefreak.com> <4FAC40BC.1060300@hesbynett.no> <4FACBB68.2080304@hesbynett.no> <4FACCAC8.4020206@pocock.com.au> <4FAD9283.7020809@hardwarefreak.com> <4FBA8EA9.40203@hardwarefreak.com> <20120522093404.3ffaae42@notabene.brown> <4FBB33D6.4010101@hardwarefreak.com> <4FBB406B.7040904@hesbynett.no> <4FBCE2C2.6030909@hardwarefreak.com> <4FBD3F49.5060005@hesbynett.no> <4FBD76F1.80400@hardwarefreak.com> Reply-To: stan@hardwarefreak.com Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4FBD76F1.80400@hardwarefreak.com> Sender: linux-raid-owner@vger.kernel.org To: stan@hardwarefreak.com Cc: David Brown , NeilBrown , CoolCold , Daniel Pocock , Roberto Spadim , Phil Turmel , Marcus Sorensen , linux-raid@vger.kernel.org List-Id: linux-raid.ids On 5/23/2012 6:46 PM, Stan Hoeppner wrote: > On 5/23/2012 2:49 PM, David Brown wrote: > >> It looks like Shaohua Li has done some testing, found that there is a >> slow-down even with just 2 or 4 disks, and has written patches to fix it >> (for raid1 and raid10 so far), which is very nice. > > Ahh, thanks David. I wasn't aware of Shaohua Li's > work on this. Got a link to his documentation and patches, or article, > by chance? My Google searches only turn up Shaohua Li's TRIM patches. I don't believe the issue we're discussing has anything to do with TRIM, though I can't be 100% sure as Mark didn't provide much detail of his thread ceiling problem, and I don't have a suitable system to do proper testing. Again it would be nice to have a link to Shaohua Li's work to which you refer to determine if it's applicable to this issue. -- Stan