Monday, October 29, 2007

Nokia 770 backup

The ssh package for the Nokia comes with sftp for file transfer. I thought to do backups by creating a big tar file and using sftp over WiFi to get a copy to my desktop. This is not an ideal solution, as one needs to create the whole archive before starting a transfer. That means you have to have enough space to create the archive. Now, the archive could take less than half of your space because tar doesn't waste any space in the last blocks of files, and the entire archive could be compressed.

But the ssh package also comes with scp. The -r option recurses directory trees, and the -p option preserves file modes. The -q option eliminates the messages about what file it's working on, and how far it has gotten, and how long it thinks it will take to finish. I've no idea how long it really takes. Just plug it into AC, connect to the backup machine via WiFi, start the scp, and call it a night.

On the backup machine, running linux, i use my mcmp program to detect files that are, in fact, identical to other files brought over from, for example, previous backups. It can create hard links from one to another, so the backup files only take filesystem space for files that actually changed. For me, that's not alot. Mostly what i do is copy books and audio to it. Reading these things does not cause the files to change. I really should release mcmp. It's fast and reliable.

The desktop computer is also backed up. I plug an external USB hard disk in, and tell it to make a copy. When it's done, i dismount the backup drive and power it down. That way a power spike can't take out both the primary and backup. Single files can be restored, if needed.

Do you have a backup plan for your computer(s)?

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