[Linux-cluster] Finding out properties of GFS formatted partition

[Bob Peterson]

On Fri, 2008-01-18 at 18:47 +0000, Christopher Probst wrote:
> Hello,
> 
> This is my first post/question on this mailing list, so I am sorry if
> the question sound naive. I have a GFS formatted partition(dev/hdb1)
> that is assigned to a cluster. I would like to know, if I can extract
> the following info of a particular GFS formatted partition
> 
> 1) Cluster name it is assigned to
> 2) Number of journals;
> 3) lock method used.
> 
> Is there any way to do this without getting a mount point involved?
> 
> Thank you in advance
> Christopher

Hi Christopher,

1. Cluster name is easy:
   gfs_tool sb /dev/sdb1 table
2. Number of journals is a bit more difficult.  If the FS is mounted
   you can do:    gfs_tool df <mount point>
   However, since you said "without getting a mount point involved" I'll
   assume that it's not mounted.  You can still find out the number of
   journals.  In RHEL5, Centos5 and equivalent, you can do this:
   gfs2_edit -p jindex /dev/sdb1
   (The gfs2_edit program recognizes gfs1 file systems as well as gfs2)
   I'll warn you that the output is not very user-friendly.

   In RHEL4, Centos4 and equivalent there's no "good" way unless the
   file system is mounted (again, use gfs_tool df).  There is a "not
   so good" way, which is to use "gfs_edit" to poke around, but you've
   got to know what you're doing.  You basically have to jump from the
   superblock to the jindex and see how many entries are there.
   Unlike gfs2_edit, gfs_edit is primitive and has no print option.

   It may not be relevant at this point in time, but for gfs2 starting
   when RHEL5.2 is released (I think), I also added:
   "gfs2_tool journals <mountpoint>".
3. Lock method is easy:
   gfs_tool sb /dev/sdb1 table

Regards,

Bob Peterson
Red Hat GFS