Scott Mcdermott wrote:
> 
>    - the largest filesystem backed up must be smaller than the size of
>      the tapes used (possibly after compression is considered)
> 

Correct.

>    - amanda can't do hardware compression without breaking easily
> 

AMANDA *can* do hardware compression. You shouldn't use both hardware
and software compression.

>    - amanda doesn't do parallel backups under any circumstances
> 

If AMANDA does not write to tape, but to the holding disk, then she
*does* dump in parallel, taking under consideration the spinning number
in the disklist entries, so that disk thrashing is avoided.


>    - I have some filesystems that are LARGE and have no hope of fitting
>      on a single tape, and no hope of fitting in a staging/holding area
>      on a disk.  These are large logical volumes that span across
>      multiple RAID arrays.  Amanda simply can't handle these because it
>      can't span tapes, correct?
> 

Yes, if you use dump, no if you use tar and exclude lists to define
directories, instead of devices to be dumped.


>    - I have a nice fast compression ASIC in my tape drives which can
>      probably compress at the drive's write speed, while my backup host
>      is slow and intended mainly for IO.  Do I have it right that Amanda
>      can't just write until EOT (allowing the drive to compress), rewind
>      to last EOF, and move on to the next tape? Instead I have to use
>      CPU in my backup server to do compression?
> 

I think you *will* be able to use your drive's compression. A file that
does not make it to the tape is not considered as "dumped", so it will
be "delayed" and tried the next run.

>    - my library has 4 drives in it, which can all write at once.  Do I
>      need to go out and buy 3 more backup hosts, split up my changer's
>      SCSI bus and partition the library into 4 virtual libraries in
>      order to actually do concurrent backups? Maybe I can run separate
>      amdump instances that don't know anything about each other? ugh :)
> 

You can't run multiple AMANDAs concurrently, that's right. They will
complain that "another copy is running". So I don't know how you can get
all 4 drives run concurrently :-( . But don't give up, ther must be a
way... run in a chrooted environment perhaps?


-- 
Regards

Chris Karakas
http://www.karakas-online.de