I'm an admin (and coder) for a very active phpBB forum. Yesterday, my host's MySQL database server crashed and they had to restore their backups from the previous day. I was using the great phpBB "Auto Database Backup
" extension written by pico88 (seriously, it's great, install it now), but that had just executed after they restored a 7 day old database, so the previous one was 24 hours old. My host's own backups was from earlier in the morning, which I had to use since it was the newest. In the end, we lost about 14 hours of posts, topics, etc. which just happen to be the most popular times of the day.
So I decided to write my own cron job to do hourly backups and store the files both locally on server and in DropBox for offsite storage. I posted instructions and source code on my personal blog
in hopes that this doesn't happen to other forums like it did with us.
For speed/performance, our .SQL file created from the sqldump is around 500mb. Using gzip compression, it's around 130mb. The sqldump takes about 10 seconds, the gzipping/tar takes about 30 seconds. Not sure how long it takes for uploading to DropBox.
If you have any questions, just let me know here or post comments to the blog.