On Wednesday, September 22, 2010 08:48:40 pm Dustin J. Mitchell did opine:
> On Wed, Sep 22, 2010 at 10:07 AM, Jon LaBadie <[email protected]> wrote:
> > Any thoughts on how desireable you feel be a separate
> > copy of amanda data would be and other approaches?
>
> This comes up often, and I've never found a solution I'm happy enough
> with to make the "official" solution.
>
> Gene's approach is the obvious one, but has a few limitations:
>
> - What do you do if you run out of space on that tape? Start a new
> tape? How do you reflect the use of that new tape in the catalog?
>
> - How does recovery from that metadata backup work? There's a
> chicken-and-egg problem here, too - you'll need an Amanda config to
> run any Amanda tools other than amrestore.
>
> Let's break down "metadata" into its component parts, too:
> 1. configuration
> 2. catalog (logdir, tapelist)
> 3. indexes
> 4. performance data (curinfo)
> 5. debug logs
>
> Configuration (1) can be backed up like a normal DLE. The catalog (2)
> should technically be recoverable from a scan of the tapes themselves,
> although the tool to do this is still awaiting a happy hacker to bring
> it to life. Indexes (3) are only required for amrecover, and if your
> Amanda server is down, you likely want whole DLEs restored, so you
> only need amfetchdump. Performance data (4) will automatically
> regenerate itself over subsequent runs, so there's no need to back it
> up. Similarly, debug logs (5) can get quite large, and generally need
> not be backed up.
>
> So, to my mind, the only component that needs special handling is the
> catalog, and we have a menu of ways to handle that:
>
> - append a copy of the entire catalog to the last tape in each run
> (hey, what is the "last tape" now that we have multiple simultaneous
> tapers?)
>
> - append a copy of only the catalog for that run to the last tape in
> each run
>
> - finally get around to writing 'amrecatalog'
>
> - rsync the entire catalog to another machine nightly
>
> I just stuck that last one in because it was my technique back when I
> managed a fleet of Amanda servers. Each would simply rsync its config
> and catalog to the other servers. Since they were all backing up to
> shared storage (a SAN), I could do a restore / amfetchdump / recovery
> of any dump on any server without trouble. It's a very
> non-Amanda-centric solution, but it's *very* effective.
>
> Dustin
And TBT, Dustin, if that other server is known to also be a 24/7 machine,
that sounds like a jolly good idea. My milling machines drive, a 60Gb,
would have more than enough space to do that, also including an image of
/home/amanda. But its uptime is possibly not on a par with this box when
the weather & power supplies might take it down.
--
Cheers, Gene
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Misery no longer loves company. Nowadays it insists on it.
-- Russell Baker
