features: append, span tapes, compress?
2003-01-23 02:25:03
After searching around in the FAQ-O-MATIC, current projects page, and in
the mailing list archives, I believe what I understand is that:
- the largest filesystem backed up must be smaller than the size of
the tapes used (possibly after compression is considered)
- amanda can't do hardware compression without breaking easily
- amanda doesn't do parallel backups under any circumstances
do I understand these points correctly? I have several issues this will
create for me and no idea how to solve them:
- 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?
- 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?
- 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 :)
A lot of the FAQs and stuff have $Id$ strings from eg 2000, so I'm
hoping that a lot of this is stale information and Amanda can actually
be used in shops with non-trivial backup requirements (after all if it
is used for a UMD, those folks must have huge backup requirements)...
Anyone know if I am mistaken, or have workarounds to address these
issues?
Any help or comments are greatly appreciated.
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