[Patch v2 4/4] kexec-kdump-howto.txt: add the behavior change of 'path' to path section

[Baoquan He]

On 03/17/14 at 11:40am, Vivek Goyal wrote:
> On Mon, Mar 17, 2014 at 03:49:20PM +0800, Baoquan He wrote:
> > Now it's time to change the behavior of 'path'. If no target is specified
> > explicitly in /etc/kdump.conf, the 'path' will be chcked if any separate
> > file system is mounted on any tier of 'path'. If no mount, vmcore is written
> > into root file system. If yes, vmcore will be wirtten into the mounted
> > file system with the left path relative to mountpoint.
> 
> We need to put some text in kdump.conf man page. Also need to modify
> kdump.conf.

Yes, this make sense. Will add in new post.

> 
> > 
> > Signed-off-by: Baoquan He <bhe at redhat.com>
> > ---
> >  kexec-kdump-howto.txt | 6 ++++++
> >  1 file changed, 6 insertions(+)
> > 


I have to say yours is great, will use it.

> 
> These "Note" are showing everywhere in the kexec-kdump-howto.txt file and
> they don't look good.
> 
> So let us not add another "Note". Let us just cleanup the whole
> description of "path". I think existing description itself is not fully
> correct and is twisted.
> 
> How about following.
> 
> Path
> ====
> "path" represents the file system path in which vmcore will be saved.
> If a dump target is specified in kdump.conf, then "path" is relative to the
> specified dump target. For example, if dump target is "ext4 /dev/sda", then
> dump will be saved ni "$path" directory on /dev/sda.
> 
> Same is the case for nfs dump. If user specified "nfs foo.com:/export/tmp/"
> as dump target, then dump will effectively be saved in
> "foo.com:/export/tmp/var/crash/" directory.
> 
> Interpretation of path changes a bit if user has not specified a dump
> target explicitly in kdump.conf. In this case, "path" represents the
> absolute path from root. And dump target and adjusted path are arrived
> at automatically depending on what's mounted in the current system.
> 
> Following are few examples.
> 
> path /var/crash/
> ----------------
> Assuming there is no disk mounted on /var/ or on /var/crash, dump will
> be saved on disk backing rootfs in directory /var/crash.
> 
> path /var/crash/ (A separate disk mounted on /var)
> --------------------------------------------------
> Say a disk /dev/sdb is mouted on /var. In this case dump target will
> become /dev/sdb and path will become "/crash" and dump will be saved
> on "sdb:/crash/" directory.
> 
> path /var/crash/ (NFS mounted on /var)
> -------------------------------------
> Say foo.com:/export/tmp is mounted on /var. In this case dump target is
> nfs server and path will be adjusted to "/crash" and dump will be saved to
> foo.com:/export/tmp/crash/ directory.
> 
> Thanks
> Vivek