Friday, 13 December 2013

Setting up bup as my backup system, making it act like a timemachine.

This is one of those: 'writing this post to make sure I remember how I've done this'.

+William Stein posted about bup which he is using to backup +The Sagemath Cloud (if you haven't seen that before make sure you go check it out, here's a video in which I describe it:

bup is a piece of backup software based on git. Here's a talk by +Zoran Zaric explaining it:

The documentation isn't too great for bup, this is the blog post I found the most helpful on it:

the ubuntu man pages are also pretty helpful.

Anyway, here's how I setup bup to work like apple's time machine.

Once bup is installed (super easy following readme instruction on Mac OSX and ubuntu). I run:

$ bup -d pathtochosenharddrive init

By default bup uses the ~/.bup directory for everthing. Using the -d flag tells bup to run whatever command (in the above instance: init)  in a chosen hard drive. If you're happy to backup to your ~ then ignore all instances of -d pathtochosenharddrive in the following. (Note you can also change $BUP_DIR to take care of this, and you'll also need to know the path to your given hard drive).

This initialises a git repository (you only need to do this once really).

I put the following in a script (

bup -d pathtochosenharddrive index -ux /directorytobackup
bup -d pathtochosenharddrive save -n backupname /directorytobackup

The first line indexes the files (the -ux flags are something to do with recursively going through the files: type man bup index to read more). The second line checks the index and then saves all files as required (giving them a name).

To setup this backup script to run every hour I write the following to a txt file (crontab.txt):

0 */1 * * * globalpathtobackupscript/

To add this to the cron jobs:

$ crontab crontab.txt

If you type:

$ crontab -l

You should see the the contents of the crontab.txt file now added to the scheduled jobs. The first 0 implies that it'll run at the 0th minute, the */1 means every one hour (so you can easily change this), the other * mean 'every', day, month and day of the week.

The first time you run this it should take a fair while (especially if you're backing up your whole ~) but afterwards it shouldn't take too long at all.

To check what bup has done, run:

$ bup -d pathtochosenharddrive ls

That should return:


and/or any other names of backups. If you want to see the actual backup snapshots:

$ bup -d pathtochosenharddrive ls backupname

which will return a list of timestamped snapshots.

This has been working pretty seamlessly for a week for me now and I'm probably going to set it up on my work Mac instead of timemachine.