[CentOS-devel] Back-port md raid1/10 BIO_RW_SYNC patch for DRBD

Thu Mar 1 05:24:19 UTC 2007
Ross S. W. Walker <rwalker at medallion.com>

> -----Original Message-----
> From: centos-devel-bounces at centos.org 
> [mailto:centos-devel-bounces at centos.org] On Behalf Of Ross S. 
> W. Walker
> Sent: Thursday, March 01, 2007 12:17 AM
> To: The CentOS developers mailing list.
> Subject: RE: [CentOS-devel] Back-port md raid1/10 BIO_RW_SYNC 
> patch for DRBD
> 
> > -----Original Message-----
> > From: centos-devel-bounces at centos.org 
> > [mailto:centos-devel-bounces at centos.org] On Behalf Of Ross S. 
> > W. Walker
> > Sent: Thursday, March 01, 2007 12:03 AM
> > To: The CentOS developers mailing list.
> > Subject: RE: [CentOS-devel] Back-port md raid1/10 BIO_RW_SYNC 
> > patch for DRBD
> > 
> > > -----Original Message-----
> > > From: centos-devel-bounces at centos.org 
> > > [mailto:centos-devel-bounces at centos.org] On Behalf Of Ross S. 
> > > W. Walker
> > > Sent: Wednesday, February 28, 2007 11:32 AM
> > > To: The CentOS developers mailing list.
> > > Subject: RE: [CentOS-devel] Back-port md raid1/10 BIO_RW_SYNC 
> > > patch for DRBD
> > > 
> > > > -----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.
> > > 
> > 
> > Ok, I just updated to that kernel, 
> > kernel-2.6.9-42.0.10.plus.c4, and I do not see the patch in there?
> > 
> > Did it miss the final cut?
> 
> My bad I spoke too soon, it is in there as 
> linux-2.6.9-raid-bio-rw-sync.patch.
> 
> Sorry,

Again, I don't want to be alarmist but... I think there might be a build
problem with the latest plus kernel:

[root at mfg-nyc-iscsi2 make]# rpm -qa | grep kernel | sort
iscsitarget-kernel-smp-0.4.14-98_2.6.9_42.0.8.plus.c4
kernel-doc-2.6.9-42.0.10.plus.c4
kernel-ib-1.0-1
kernel-module-drbd-2.6.9-42.0.3.plus.c4smp-0.7.21-1.c4
kernel-module-drbd-2.6.9-42.0.8.plus.c4smp-0.7.23-1.c4
kernel-smp-2.6.9-42.0.10.EL
kernel-smp-2.6.9-42.0.8.plus.c4
kernel-smp-devel-2.6.9-42.0.10.EL
kernel-utils-2.4-13.1.83

Looks like the plus kernel dependencies got mixed up...

[root at mfg-nyc-iscsi2 make]# ls -l /lib/modules/
total 32
drwxr-xr-x  3 root root 4096 Feb 28 23:45 2.6.9-42.0.10.ELsmp
drwxr-xr-x  2 root root 4096 Dec 22 23:13 2.6.9-42.0.3.EL
drwxr-xr-x  3 root root 4096 Feb  2 17:31 2.6.9-42.0.3.ELsmp
drwxr-xr-x  4 root root 4096 Feb 24 11:13 2.6.9-42.0.3.plus.c4smp
drwxr-xr-x  4 root root 4096 Feb 28 23:45 2.6.9-42.0.8.plus.c4smp
drwxr-xr-x  2 root root 4096 Dec 22 23:12 2.6.9-42.EL
drwxr-xr-x  2 root root 4096 Feb 27 09:53 kabi-4.0-0smp

And it's gone and installed the standard kernel.

-Ross

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