@ToxicFrog Gotcha, thank you for clarifying! Is there a way to use multiple indices? Seems like you lose the benefit of having an index if you have to --clear and rebuild each time if you're doing multiple different directories, unless I've understood incorrectly
@bertieb so, first all, you don't need to clear unless there's stuff in the index that will result in files in the backup you don't want; depending on how you want to use it, this may be a non-issue even if you're using the same index for multiple different backups
Like, if you're backing up /home sometimes and /srv sometimes, but always as bup save /home or bup save /srv, you can use the same index for both
It only becomes a problem if you (e.g.) want all your backups to look like they're rooted at /, so you're going bup index /home; bup save / and bup index /srv; bup save /
@bertieb if you do need multiple indexes, both bup index and bup save let you specify a custom index file with -f /path/to/index
The default is $BUP_DIR/bupindex, with $BUP_DIR defaulting to $HOME/.bup/
(note that $BUP_DIR/index, if present, is the git index -- bup repos are git-compatible, although large ones will cause some git commands to choke -- so don't use that if you plan to use git commands to do anything with your bup repos.)
@ToxicFrog Okay fair enough. I wondered as I have other filesystems mounted under $home (no real need to other than it's what I'm used to now) and wanted to backup up some but not all of the mounts separately
(hit enter too soon)
I was hoping there would be an -x flag for bup save as well to keep it within a filesystem, though I guess I could use different --exclude options alternatively
Just a bit more to get my head around than rdiff-backup, so I appreciate you enlightening me :)
bup save is, by design, really dumb; all the smarts in deciding what to back up are in bup index.
I note that if you do something like bup index -x /home; bup save /home, if anything was recorded under those mountpoints in a previous save it'll still be there in the new one, but bup save won't actually read the contents of those mountpoints -- the index says they haven't changed since last time, so it just re-uses the trees that already exist in the data store.
Basically, when you run bup index, it scans all the paths given, and any that are missing from the index, or have a different state, it adds to the index and marks it as needs to be backed up.
When you run bup save, it looks at all the paths in the index that are (a) under the paths you told it to save and (b) marked as needs backup, and reads those from disk and saves them; everything that matches (a) and not (b) it re-uses whatever is already saved.
Mine will run the server (with attached disk arrays) for about 40-60 minutes, depending on load, and then the WAP, switch, and modem for another hour or two after the server shuts down
(which is handy for laptops/phones in an extended power outage)
That said, it's primarily useful for keeping continuity through short power outages common in midsummer (because everyone is cranking the AC) and midwinter (because trees keep falling on the power lines)
