I read this post on Joey Hess’ blog which expresses a thought I’ve been having: one shouldn’t rely on version control for backups in the disaster-recovery sense of backups, but just for history and synchronisation between machines. The reason for this is that while I do have some automatic checking-in, use of version control means that large chunks of important stuff is not safe until you check it in and you won’t do this regularly enough: it’s too annoying. And of course there is all the stuff that is (sensibly) not in git or git-annex, such as my ~/tmp/ which is actually my desktop. A backup of that would save my mental energy consumed by remembering to check stuff in.

Obnam has many feature conducive to this. There is even a continuous backup feature on the roadmap, though you don’t really need this, just run every 20 minutes in a cronjob, with the main exclusion being /home/swhitton/var/.git/annex/objects which git-annex can deal with. What makes it shine for my purposes is the multi-client de-duplication: it can avoid storing two copies of identical files that exist on both my laptop and desktop. But at the moment it’s just too slow for the transatlantic backups I need to use (only off-site location I have enough disc space) due to the way it iterates through SFTP commands. The author says that he’s going to work on this once he’s fixed outstanding bugs.

I dream of the day when stable, suffiently-featured versions of Emacs 24, git, git-annex, Org-mode, vcsh, mr and obnam are available in Debian Stable for all architectures and in Raspbian, and this version of Debian Stable is ubiquitous enough that you can get your friendly sysadmin to apt-get them for you and you have it all everywhere.