Re: features: append, span tapes, compress?
2003-01-23 18:48:09
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
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- Re: features: append, span tapes, compress?, (continued)
- Re: features: append, span tapes, compress?, John R. Jackson
- Re: features: append, span tapes, compress?, Jon LaBadie
- Re: features: append, span tapes, compress?, Brian Cuttler
- Overland XB tape stacker, Nigel Barker
- Re: Overland XB tape stacker, Chris Dahn
- Re: Overland XB tape stacker, Jay Lessert
- Re: features: append, span tapes, compress?, John R. Jackson
- Re: features: append, span tapes, compress?, Brian Cuttler
Re: features: append, span tapes, compress?,
Chris Karakas <=
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