Actually, by "backup tools" I meant "tools for when other tools fail", not "tools for making backups",
Oh! Oops... I saw ftp and Kermit etc being systems for moving data about, that being roughly what backing-up involves...
All I ever used extensively under *ix was tar, but tar did what I needed it to do. I'm mostly hoping that once I install a Jumbo drive in a Linux box it'll work just like the old QIC-20 drives did way back when, and spare me having to climb a learning curve.
*nod* Tar's what I'm still planning to use. I expect you know the Ftape driver is still supported on Linux, and there's an "FTape HOWTO" if that's of use to you :)
Appending to a tape would have been/will be useful, but I never quite trusted it, so I never really used that feature.
*nod* I've heard that it can trounce existing data, so the scheme I had in mind was to rotate through a set of 3 tapes, 1 a day, putting the latest L2 backup at the end. That way, whatever got damaged, if anything, should be stale data, and the previous working backup should be on another tape. L1s I hope to put on 2 alternating tapes in similar fashion, maybe once a week. L0/full backups wouldn't be appended because they'd be far too big, and I plan on doing them for separate "areas" of the filesystem to reduce the time for each one.
Unfortunately I get the impression looking again, that you can't remove a DDS tape without rewinding the thing, so it'd need to be fast forwarded each time. The main point of appending to tapes would be to avoid wearing the start of the tape out, and I'm not sure if that'd still apply in this case. Of course, you're still supposed to "retension" the things anyway :P
A key element in both setups was that the cron script wrote the tape with "tar cv" then rewound it and did a "tar tv" to check whether each file that the first pass said it was writing was actually there
Yeah, I was thinking something like that too. Very wise :)
I think I played with 'tar u' and wound up deciding to use 'find / -newer archive-datestamp' for incremental backups instead
The recent versions of gnutar seem to have an even more useful system for this that also stores info about files that have gone, using the -G and -g options. These are for creating new incremental archives though, rather than altering existing ones.
I don't know about tar's blocking factor interacting with gzip (I should go read the gzip man page now)
Yeah, I got what the blocking factor was for, but I had various confusions about it. As I've not been able to unearth much more info on tar and tapes, I'll probably ask on an appropriate tech support type forum. Thanks for your suggestions! :)
Re: Backups
*nod* Tar's what I'm still planning to use. I expect you know the Ftape driver is still supported on Linux, and there's an "FTape HOWTO" if that's of use to you :)
*nod* I've heard that it can trounce existing data, so the scheme I had in mind was to rotate through a set of 3 tapes, 1 a day, putting the latest L2 backup at the end. That way, whatever got damaged, if anything, should be stale data, and the previous working backup should be on another tape. L1s I hope to put on 2 alternating tapes in similar fashion, maybe once a week. L0/full backups wouldn't be appended because they'd be far too big, and I plan on doing them for separate "areas" of the filesystem to reduce the time for each one.
Unfortunately I get the impression looking again, that you can't remove a DDS tape without rewinding the thing, so it'd need to be fast forwarded each time. The main point of appending to tapes would be to avoid wearing the start of the tape out, and I'm not sure if that'd still apply in this case. Of course, you're still supposed to "retension" the things anyway :P
Yeah, I was thinking something like that too. Very wise :)
The recent versions of gnutar seem to have an even more useful system for this that also stores info about files that have gone, using the -G and -g options. These are for creating new incremental archives though, rather than altering existing ones.
Yeah, I got what the blocking factor was for, but I had various confusions about it. As I've not been able to unearth much more info on tar and tapes, I'll probably ask on an appropriate tech support type forum. Thanks for your suggestions! :)