[Linux-cluster] problem adding new node to an existing cluster

Greenseid, Joseph M. Joseph.Greenseid at ngc.com
Tue Jan 6 13:57:21 UTC 2009

---- "Joseph M. Greenseid" <Joseph.Greenseid at ngc.com> wrote:
| Hi,
| I have a new question.  When I created this file system a year ago, I
| didn't anticipate needing any additional nodes other than the original
| 3 I set up.  Consequently, I have 3 journals.  Now that I've been told
| to add a fourth node, is there a way to add a journal to an existing
| file system that resides on a volume that has not been expanded (the
| docs appear to read that you can only do it to an expanded volume
| because the additional journal(s) take up additional space).  My file
| system isn't full, though my volume is fully used by the formatted GFS
| file system. 
| Is there anything I can do that won't involve destroying my existing
| file system?
| Thanks,
| --Joe

> Hi Joe,

> Journals for gfs file systems are carved out during mkfs.  The rest of the
> space is used for data and metadata.  So there are only two ways to
> make journals: (1) Do another mkfs which will destroy your file system
> or (2) if you're using lvm, add more storage with something like
> lvresize or lvextend, then use gfs_jadd to add the new journal to the
> new chunk of storage.

Ok, so I did understand correctly.  That's at least something positive.  :)

> We realize that's a pain, and that's why we took away that restriction
> in gfs2.  In gfs2, journals are kept as a hidden part of the file system,
> so they can be added painlessly to an existing file system without
> adding storage.   So I guess a third option would be to convert the file
> system to gfs2 using gfs2_convert, add the journal with gfs2_jadd, then
> use it as gfs2 from then on.  But please be aware that gfs2_convert had some
> serious problems until the 5.3 version that was committed to the cluster
> git tree in December, (i.e. the very latest and greatest "RHEL5", "RHEL53",
> "master", "STABLE2" or "STABLE3" versions in the cluster git (source code)
> tree.)  Make ABSOLUTELY CERTAIN that you have a working & recent backup and
> restore option before you try this.  Also, the GFS2 kernel code prior to
> 5.3 is considered tech preview as well, so not ready for production use.
> So if you're not building from source code, you should wait until RHEL5.3
> or Centos5.3 (or similar) before even considering this option.

Ok, I have an earlier version of GFS2, so I guess I'm going to need to sit down and figure out a better strategy for what I've been asked to do.  I appreciate the help with my questions, though.  Thanks again.


> Regards,
> Bob Peterson
> Red Hat GFS

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