Re: Question about vtape size

On Thu, Feb 02, 2006 at 10:01:45AM -0500, Jon LaBadie wrote:
> How are current users sizing their vtapes and what has
> been their experience in disk usage?

Here is what I am currently doing:

size of vtapes is set to DVD size.

I have written a tape-changer with the capability to be set in
"offline" mode.  All over the week, the changer is set to "offline",
thus I circumvent amanda's balancing strategies.  Incrementals cummulate
in the holding area.  Holding area is copied to a USB disk after backup.
I have two USB disks for this which I change once a day. Thus, in case of
a disaster, I loose at most one day of backups. Copies of holding-areas
which are older than 2 weeks are deleted from the USB disk.

At friday night, cron forces all DLEs to level 0 and sets the changer to
"online".  Along with autoflash, I get all the incrementals and a full
dump of every DLE on the vtapes.

At saturday, with the help of a script, I:
 1. burn/verify all this to DVD's,
 2. print the labels,
 3. empty all vtapes that are already burned _and_ older than 2 weeks


This setup has following advantages:

1. 2 weeks of backups are directly available from the vtape area without
   fiddling with DVDs.
2. Needed disk size is limited to roughly 2 times of the sum of all DLEs,
   no matter how many vtapes are used.
3. I have at least two copies of everything that is younger than two weeks.
   (exception is the level0 that was done at saturday morning.  They will
    go to DVD only at the afternoon on the same day).
4. Since every packet of DVDs that I burn at saturday is a full backup of
   all my DLEs, it is pretty easy to put some of them away for long-time
   archival.
5. I am involved to the process only once a week.

And here is the disadvantage:

1. Number and size of DLEs is limited.  Burning 100 DVDs in one afternoon
   is not very likely to be realistic ;-)
2. I am involved to the process once a week. :-)


I think the disadvantages could be resolved with a real tapechanger and
some scripting.  But a real tapechanger is much too expensive for me, so
I prefer to accept the disaadvantages :-)