Re: multipath-tools libmultipath/configure.c libmu ...

[Benjamin Marzinski <bmarzins@redhat.com>]

On Fri, Sep 19, 2008 at 04:57:32PM -0500, Andy wrote:
> On Fri, Sep 19, 2008 at 01:53:13PM -0500, Andy wrote:
> > On Fri, Sep 19, 2008 at 03:27:10AM -0000, bmarzins@sourceware.org wrote:
> > > CVSROOT:	/cvs/dm
> > > Module name:	multipath-tools
> > > Branch: 	RHEL5_FC6
> > > Changes by:	bmarzins@sourceware.org	2008-09-19 03:27:08
> > > 
> > > Modified files:
> > > 	libmultipath   : configure.c configure.h devmapper.c devmapper.h 
> > > 	multipathd     : cli.c cli.h cli_handlers.c cli_handlers.h 
> > > 	                 main.c main.h 
> > > 
> > > Log message:
> > > 	Fix for bz #455692. There is now a command for multipathd, 'resize map'. This
> > > 	does online grows or shrinks for your multipath device. It has some warts.
> > > 	
> > > 	1. It needs to remove and re-add every path in the device. This can cause two
> > > 	annoyances. First, if you only have one valid path, you go into an all paths
> > > 	down scenario. However, you will immediately re-add the path, so it won't
> > > 	trigger problem #2. Second, if the path is inaccessable, you may not be able to
> > > 	re-add it.
> > > 	
> > > 	2. You can't disable flushing on suspend for a device-mapper device, when you
> > > 	want to change size. This means that if all your paths are down, you will fail
> > > 	the queued IOs when you suspend. This is a problem with the device-mapper kernel
> > > 	code, and there's no real way to avoid it, except by fixing it in the kernel.
> > > 	
> > > 	This commit also has some minor fixups for 238421, and adds the ability to
> > > 	disable and restore queueing on all multipath devices through multipathd
> > > 
> > > Patches:
> > > http://sourceware.org/cgi-bin/cvsweb.cgi/multipath-tools/libmultipath/configure.c.diff?cvsroot=dm&only_with_tag=RHEL5_FC6&r1=1.2.2.3&r2=1.2.2.4
> > > http://sourceware.org/cgi-bin/cvsweb.cgi/multipath-tools/libmultipath/configure.h.diff?cvsroot=dm&only_with_tag=RHEL5_FC6&r1=1.1&r2=1.1.2.1
> > > http://sourceware.org/cgi-bin/cvsweb.cgi/multipath-tools/libmultipath/devmapper.c.diff?cvsroot=dm&only_with_tag=RHEL5_FC6&r1=1.22.2.5&r2=1.22.2.6
> > > http://sourceware.org/cgi-bin/cvsweb.cgi/multipath-tools/libmultipath/devmapper.h.diff?cvsroot=dm&only_with_tag=RHEL5_FC6&r1=1.11.2.4&r2=1.11.2.5
> > > http://sourceware.org/cgi-bin/cvsweb.cgi/multipath-tools/multipathd/cli.c.diff?cvsroot=dm&only_with_tag=RHEL5_FC6&r1=1.5.2.2&r2=1.5.2.3
> > > http://sourceware.org/cgi-bin/cvsweb.cgi/multipath-tools/multipathd/cli.h.diff?cvsroot=dm&only_with_tag=RHEL5_FC6&r1=1.5.2.2&r2=1.5.2.3
> > > http://sourceware.org/cgi-bin/cvsweb.cgi/multipath-tools/multipathd/cli_handlers.c.diff?cvsroot=dm&only_with_tag=RHEL5_FC6&r1=1.6.2.2&r2=1.6.2.3
> > > http://sourceware.org/cgi-bin/cvsweb.cgi/multipath-tools/multipathd/cli_handlers.h.diff?cvsroot=dm&only_with_tag=RHEL5_FC6&r1=1.3.2.2&r2=1.3.2.3
> > > http://sourceware.org/cgi-bin/cvsweb.cgi/multipath-tools/multipathd/main.c.diff?cvsroot=dm&only_with_tag=RHEL5_FC6&r1=1.69.2.13&r2=1.69.2.14
> > > http://sourceware.org/cgi-bin/cvsweb.cgi/multipath-tools/multipathd/main.h.diff?cvsroot=dm&only_with_tag=RHEL5_FC6&r1=1.7&r2=1.7.2.1
> > > 
> > 
> > Where can I get the multipath-tools sources that these patches apply cleanly
> > to?  They do not apply cleanly to my multipath 0.4.8 sources, add there
> > seems to be some major differences in some places.
> > 
> > Thanks,
> > 
> > Andy
> > 
> 
> Responding to my own mail, I did got the source with the patches from the
> cvs.  But, the resizing does not work for with with mounted volumes.  There
> are 4 paths for the volume, so there is no probably with it failing paths. 
> I get "domap(0) failure for create/reload map" when I run multipath -v 3.
> 
> I can get dm to reconize the new size if the volume is umounted.  But, I
> really would like it to work while it is mounted.
> 

It should work for mounted volumes.  Did you try
multipathd -k"resize map <mapname>"

Since this requires suspending without the no_flush option, I didn't
want to have it happen on a normal reload, and since without the kernel
fixes, this required removing and then readding paths, I did it through
multipathd.

So just running multipath -v3 after a path resize won't work. In fact, I
think it might leave the devices in the suspended state, since the
resume fails.

-Ben

> Andy
> 
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