Tarsnap

I keep a personal task management system, but I don't keep it particularly well. I feel it has been more observed in the breach than actually used to keep track of critical tasks. However, I have kept it going through life events, job and role changes, COVID-19, moving and general chaos.

One consequence of this is that I have some long standing tasks in that system. These are things I mean to do,but for some reason I just don't. There are usually two reasons whey they stay on my list for a long time.

The first is that I really don't want to actually do it or there is some part of it that I don't want to do. If I don't really want to do the task, why does it stick around? Well, I probably don't want to admit to myself that I'm never going to do it.

The second reason is more interesting. This is where I don't actually have a full picture of what the task entails. This is either because I haven't thought about it enough, or because have misconceptions about it.

That was the case with my task to set up Tarsnap backups. I knew it was an interesting service and that people found it useful. What I didn't know is how to actually use it to make useful backups.

I even purchased a book about it. That helped a bit, but I still didn't know exactly how I should apply it to my use case.

My first attempt was to back up a large amount of data one single time. It worked, but I blew through my money on the service too quickly. It was not a lot of money, the service is inexpensive, but it told me that I had chosen the wrong data for that task. I have since backed up that original data to physical media and stored it at a second location.

I also made the mistake of sending emails from tarsnap to my email archive. I received, but didn't see, several emails warning me I was running out of money and my content would be deleted. So, lots of lessons learned from that first experience.

I think the reason it took me awhile to figure out tarsnap is that I've never really been responsible for either tape backup or regular backup for a work system. Since tarsnap emulates that, I didn't really have a good reference. I had used tar, but mostly for un-archiving--not backing up.

My father's work had a tape backup system. I remember he had to take home the tape backups on a regular basis, just so they were off site. I remember those tapes, they actually had a metal bottom so they looked like they could survive anything.

I also remember his working having a teletype machine, which I found really interesting. We would sometimes get the really wide tractor feed paper with alternating sections of green and white. I think we were always clamouring for more paper to write on.

The part about tarsnap that I didn't get is that the backup tool doesn't dictate how you back up. The consumer-level tools that I'm more familiar with build that in, but with tarsnap you are responsible for picking a name for your backup that has the critical information like what you are backing up and the date of the backup.

Then you need to set up a system to make regular backups: say daily or weekly. It's all up to you to figure out how to prune the old backups according to your schedule.

The nice thing about tarsnap is that it handles the compression and de-duplication of your backup data. I had to think a bit about how to backup a database so that it isn't an opaque binary to tarsnap. And I also learned you want to let the database software ensure that you're not backing up the data mid-transaction.

So, I may have had this task on my list for a long time, but I'm really glad to be finally using tarsnap for something that is very useful for me.

Maybe that means I'll finish off some other long-standing tasks.

Posted on October 24, 2025.