One year ago I posted a blog entry about my fireproof backup. The backup is still in place today, and prevented the loss of multiple days of work, but there was some occasional problems at the beginning that could be interesting to share.
The first disk I used died after something like 3 months, probably because I opened the safe during a backup (the disk is located in the safe's door). But one's could have expected more from a disk supposed to be "ultra portable". Anyway, I bough a second disk, but there was bad sectors which created problems for the first few weeks, until I reformatted it with "mkfs.ext3 -c". I am still removing the the old backups file manually each week before the full backup, and for good measure I do also a "fsck -f" before removing the files on the disk (even if it takes more time, I learned the hard way that the fsck should be done *before* removing the files, in case fsck decide that the most recent files are corrupted...)
As for the problem that opening the safe door during the backup is not a good idea, I tried to find a way to have a visual clue on the safe itself that the disk is currently used, but without success. Something as simple as a male/female dongle that could be inserted in the USB cable, with an LED that is on when the current drained on the +5V line is above some threshold would be perfect. Another project to put on the stack...
I also would like to use a larger disk - 1.5 Tb would be perfect, as I could keep two full backups, plus two weeks of incremental backup. Currently I have to be careful and, for example, synchronize and rebuild the complete Android tree only on the day before the full backup. Unfortunately I was not able yet to find a disk powered by the USB connector that can have this capacity (but removing all the ogg files from my desktop computer, as explained in the previous blog entry, helped keeping this under control for now).
I also tried to convert my setting to USB 3.0 for accelerate the backup (it currently takes between 8 and 15 hours) - going as far as installing a USB 3.0 card in my desktop - until I realized that I cannot change the USB cable that goes inside the safe without compromising the waterproof seal.
And talking about waterproof seal, one of the problem of the safe itself is that humidity quickly build up inside the safe (probably exacerbated by the heat of the disk), so after some time the documents stored feel kind of damp. I bought a dehumidifier that did solve the problem. I just have to plug it overnight each three months or so to renew the crystals.