Out of disk space

[Syzygies]

One use that I make of SuperDuper! is to maintain an exact clone of my laptop's internal drive. The clone is the same size, because it's an identical model disk. In the event of a disk failure, I find a screwdriver and I have my laptop back in service in ten minutes.

I can't believe that I'm still regularly getting "out of disk space" errors, cloning my user partition. Usually, I have plenty of working space on my system partition, but I have 10 GB of media files that change from time to time, and less free space, on my user partition. SuperDuper! tries to write the new files before erasing the old files, and doesn't have a plan B.

If "Disk Inventory X" can find all the large files on my disk in under a minute, why can't SuperDuper! check to see which large files will be deleted, and delete them in advance? This would avoid the problem with high probability.

Alternately, if the code under the hood is sufficiently modular, it would be trivial to write a fallback "Plan B" where when SuperDuper! encounters this error, it starts over only deleted, then starts over again in normal mode.

Generally, when I get this error, SuperDuper! had plenty of time while I was gone for three such passes, but it froze like a deer in the headlights. It's times like this that I remember wanting to write a similar program as freeware.

[dnanian]

As I've said elsewhere, it is something we're looking at. Doing it quickly, efficiently and safely is a key consideration: it's mostly a very rare situation.

Given the cost of disks these days, though, it seems like giving yourself a bit more headroom in the meantime would be both cost and time effective...

[Syzygies]

Originally Posted by dnanian

Given the cost of disks these days, though, it seems like giving yourself a bit more headroom in the meantime would be both cost and time effective...

This is my usual practice. However, all three disk failures that have threatened my data have involved laptop drives that died without warning. I have bought the largest drive that will fit in my laptop, already, and I am cloning to an emergency spare. This is "sneakernet mirrored raid"; if I could find a larger 2.5" spare, I'd buy two and use one as my primary drive.

So more headroom is NOT an option, for my most critical application of SD!

If this is rare, then efficiency is not a consideration. What should SD! do if it hits this error?

1. Give up in despair.

2. Start a new pass where it only deletes, then try again with a normal pass.

I am a programmer, and I can't imagine this being more than 20 lines of code, with no impact on performance until the alternative would be 1.

[dnanian]

Can't imagine it being more than 20 lines of code? C'mon, Syzygies... as a programmer, you also likely know that everything's easy/short/trivial when you don't have to do it, bulletproof it and test it.

We have some ideas in this area. They're not what you're suggesting, no, but rather better. But it's complicated to do right...