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