On Monday 31 July 2006 19:45, Jon LaBadie wrote:
> On Mon, Jul 31, 2006 at 06:56:22PM +0100, Anne Wilson wrote:
> > After the struggle to burn my tape-split backups onto DVD, I find myself
> > wondering just how useful they are.  The current set of backups are still
> > on hard drive, but what if I want to find an earlier copy of a file which
> > has since been burned onto DVD?
> >
> > It seems to me that once vtapes are free for overwriting the
> > corresponding index will be lost too.  Can either amrestore or amrecover
> > actually access these files?
>
> Obviously not talking from experience here.
> So this is just a conceptual framework for something that might work.
> You do realize that you are, or will soon be, the leading expert
> on saving amanda backups on optical media, right?
>
Now there's a scarey thought ;-)

> Suppose you had a different config for recovery (rec-config).
> The rec-config might use nearly all the same config data and
> could use the same curinfo/log/index directories as your
> normal config.  Further, suppose you never deleted (amrmtape)
> or overwrote a vtape in your regular config (unless the dvd
> data were no longer needed).  That would keep the index and
> log files available for amrecover.
>
Never overwrite a vtape?  So it would be necessary to add vtapes from time to 
time?

> Your rec-config could use a device, maybe with chg-manual,
> that had "data" pointing to your dvd mount point (a symlink).
>
> I'm not thinking well enough to recommend how to handle the
> current vtapes.  Maybe rm the data a day or two before reuse,
> relabel the vtape with amlabel for a new label, and maybe rename
> the slot one greater than current max.
>
>
> Another totally off-the-wall brainstorm; what if you reserve
> one slot in your changer directory as a symbolic link to your
> dvd mount point.  Say it was slot99 or slot1 or ???.  Perhaps
> when amrecover asked for a particular tape you could mount
> the appropriate dvd, and ammt/amtape it to the current active
> changer position.
>
> I was thinking about that from my current installation.  My
> actual storage is on two external drives.  My changer "slot"
> directory is on the hard system's hard drive and the "slotXX"
> directories are actually symbolic links to external drive
> directories.  It could just as well point to a mounted dvd
> directory.
>
So that backup wouldn't actually write to the hard disk, but to the DVD?  If 
it did that, tape-spanning would be problematic, wouldn't it?  I can't see 
how it could work.

> Such an approach would be testable with your current setup.
> Rename the slotXX containing the original hard disk data.
> Recreate slotXX as a symbolic link to your dvd data.  Try
> amrecover.
>
> You would still need to retain index etc. and relabel hd tapes.

That's a lot to think about and experiment with.  I'll play around a little 
when I can make time.  Thanks for the ideas.

Anne

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