On 21/10/14 11:14, Chris Green wrote:
[SNIP]
That last point was my original one - the complexity of most backup systems seems to me to be such that it's often much simpler (and you get *exactly* what you want) to D-I-Y. This isn't a particular criticism of obnam, it was my starting point when I asked if the algorithm I posted some days ago looked correct.
[SNIP]
I'm not sure about the current level of support or development, but for many years we've been using rdiff-backup (www.nongnu.org/rdiff-backup). The most recent release was 2009, but it is stable and mature, and is, essentially, a front-end to rsync (well, it uses the python librsync library).
Here's the overview:
---- cut here ---- What is it?
rdiff-backup backs up one directory to another, possibly over a network. The target directory ends up a copy of the source directory, but extra reverse diffs are stored in a special subdirectory of that target directory, so you can still recover files lost some time ago. The idea is to combine the best features of a mirror and an incremental backup. rdiff-backup also preserves subdirectories, hard links, dev files, permissions, uid/gid ownership, modification times, extended attributes, acls, and resource forks. Also, rdiff-backup can operate in a bandwidth efficient manner over a pipe, like rsync. Thus you can use rdiff-backup and ssh to securely back a hard drive up to a remote location, and only the differences will be transmitted. Finally, rdiff-backup is easy to use and settings have sensical defaults." ---- cut here ----
Editorial aside: "sensical"?
It doesn't encrypt the backups, but it does use password-less keys in SSH to do the copies, can resume if the backup fails, does incrementals, and provides an instant copy of the latest version of a file.
Here's an example of the incantation using SSH, where "backup::" is specifically defined in the SSH config file:
rdiff-backup --print-statistics /usr/local backup::/backups/$CUST/$PC/$HOST/local >> /var/log/backups 2>&1
No problems yet, but it seems to have been left behind since duplicity came along. Worryingly, it is masked on Gentoo (actually, it always has been now I think about it), now with the comment: "Dead upstream, has known dataloss bugs. Please use something more sane: rsnapshot, backuppc, obnam, ..."
I've never had any data loss, but it does crap out sometimes. Never had a problem repairing any damage either.
Looking at wikipedia, there seems to be a fair quantity of stuff using rsync. Something there must be useful:
http://en.wikipedia.org/wiki/Rsync
My current requirement is that I have two clients who want to provide reciprocal off-site backup facilities. That requires encryption. So, I'll probably use rdiff-backup for the local copy (for a virtually instant local restore, with increments as well), and duplicity for the encrypted remote copies.
Cheers, Laurie.