[CentOS-devel] Back-port md raid1/10 BIO_RW_SYNC patch for DRBD
Ross S. W. Walker
rwalker at medallion.com
Wed Feb 28 16:31:53 UTC 2007
> -----Original Message-----
> From: centos-devel-bounces at centos.org
> [mailto:centos-devel-bounces at centos.org] On Behalf Of Johnny Hughes
> Sent: Wednesday, February 28, 2007 10:08 AM
> To: CentOS-Devel
> Subject: RE: [CentOS-devel] Back-port md raid1/10 BIO_RW_SYNC
> patch for DRBD
> On Wed, 2007-02-28 at 02:08 -0600, Johnny Hughes wrote:
> > On Tue, 2007-02-27 at 21:10 -0500, Ross S. W. Walker wrote:
> > > > -----Original Message-----
> > > > From: centos-devel-bounces at centos.org
> > > > [mailto:centos-devel-bounces at centos.org] On Behalf Of Ross S.
> > > > W. Walker
> > > > Sent: Sunday, February 25, 2007 12:24 PM
> > > > To: centos-devel at centos.org
> > > > Subject: [CentOS-devel] Back-port md raid1/10 BIO_RW_SYNC
> > > > patch for DRBD
> > > >
> > > >
> > > > Attention CentOS Developers,
> > > >
> > > > Here is a back-port of Lars Ellenberg's md raid1/10
> patch from 2.6.19+
> > > > to 2.6.9. It seems the md raid1 and raid10 drivers were
> stripping the
> > > > BIO_RW_SYNC flags on requests which caused a severe
> > > > performance penalty
> > > > for DRBD when writing it's meta-data to these volumes.
> > > >
> > > > The patch is attached as well as inlined:
> > >
> > > No comments?
> > I just put it in the new CentOSPlus kernel (that I am currently
> > testing).
> > Should be out later today (if it works).
> OK ... the released CentOS-Plus kernel
> (2.6.9-42.0.10.plus.c4) has that
> patch installed on x86_64 and i386 ... and I did install it and test
> with DRBD. The systems it is on are running OK.
Excellect, I am currently running the patch on my x86_64 plus kernel here
with no problems, and I have the OS booting off of RAID1, I have the
meta-data as a LVM on the OS vg and no problems and a significant
improvement with my large DRBD volumes.
Lars did review the fixes too and gave them the ok, so it wasn't
completely without review.
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