From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Majed B." Subject: Re: xfs > md 50% write performance drop on .30+ kernel? Date: Tue, 13 Oct 2009 14:09:40 +0300 Message-ID: <70ed7c3e0910130409r1e1350b6yabfdc3d4f5c51edf@mail.gmail.com> References: <66781b10910120958k4afb637ejba79e4c23900c4da@mail.gmail.com> <20091013013352.GA24869@infradead.org> <66781b10910130406s4119985fg5db7679a2e9fd4f2@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <66781b10910130406s4119985fg5db7679a2e9fd4f2@mail.gmail.com> Sender: linux-raid-owner@vger.kernel.org To: mark delfman Cc: Linux RAID Mailing List List-Id: linux-raid.ids Out of curiosity, why are you upgrading the kernel? Are you after a certain feature offered by the new kernel? If not, roll back to a kernel version where you don't face performance = drops. On Tue, Oct 13, 2009 at 2:06 PM, mark delfman wrote: > A little more information which I =E2=80=98think=E2=80=99 seems to po= int at MD..... > > Creating an EXT3 FS on an MD RAID also shows a circa 50% performance = drop. > We have tried a multitude of RAID options (raid6/0 various chunks etc= ). > > Using a hardware based raid XFS / EXT3 shows no performance drop > (although the hardware raid is significantly slower than MD in the > first place) > > We are happy to keep testing and offering anything that could be > useful, we are just a little stuck thinking of anything else to do...= =2E > > > > > On Tue, Oct 13, 2009 at 2:33 AM, Christoph Hellwig wrote: >> On Mon, Oct 12, 2009 at 05:58:20PM +0100, mark delfman wrote: >>> Hi... in recent tests we are seeing a 50% drop in performance from >>> XFS>MD on a 2.6.30 kernel (compared to a 2.6.28 kernel) >>> >>> In short: =C2=A0Performance to MD0 direct =3D circa 1.7GBsec (see b= elow), via >>> xfs circa 850MBsec. =C2=A0On previous system (2.6.28) there was no = drop in >>> performance (in fact often an increase). >>> >>> I am hopefully that this is simply a matter of barriers etc on the >>> newer kernel and MD, but we have tried many options and nothing see= ms >>> to change this so would very much appreciate advice. >> >> Did barrier support for RAID0 got introduced in 2.6.30? >> >> > -- > 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 =C2=A0http://vger.kernel.org/majordomo-info.ht= ml > --=20 Majed B. -- To unsubscribe from this list: send the line "unsubscribe linux-raid" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html