Best practices for using gjournal with gmirror?

[Craig Boston]

On Wed, Jan 10, 2007 at 11:21:01PM -0500, John Nielsen wrote:
> 5) Finally, how dangerous is this code? I realize it's experimental and only 
> plan to use it with data that has recent backups, but how much should I 
> worry about it blowing up my system or corrupting my files?

Just my personal experience, but I've found the gjournal implementation
to be extremely stable.  I'm not doing anything terribly unusual with
it, but both my laptop and my primary workstation use gjournal for all
of their filesystems except / and /tmp.  On my workstation one of the
journaled filesystems (/home) is on a mirror using the ataraid(4)
driver, but I've also successfully used it with gmirror.

I do a lot of parallel source code extraction and building and have
never run into a crash or panic that was caused by gjournal itself.
The panics and deadlocks I have encountered due to other reasons have
shown that using gjournal has actually significantly reduced the amount
of FS corruption in those events.  You still lose anything created or
changed in the last ~30 seconds or so, but that's better than a
corrupted FS.

I would still be religious about backups just in case, but it's unlikely
that gjournal will be the reason you have to use them.

Craig

* NOTE: I'm running the gjournal backport to RELENG_6.  YMMV if running
-CURRENT.