Ubuntu: Upgrading to Hardy from Gutsy, but getting apt-get errors? Solution here.

The recommended action for anyone still running 7.10 is to use the do-release-upgrade command to (relatively) painlessly upgrade to a newer, supported version of Ubuntu (remembering to take a backup first, just in case).  The one little catch with this solution is that without access to the package repository, you won’t be able to install the upgrade tool if you don’t already have it.

Fortunately, the Gutsy repository hasn’t been removed completely, it’s just relocated to old-releases.ubuntu.com.  

via blog.uncommons.org

If you're seeing things like this:
404 Not Found [IP: 91.189.88.45 80]
Err http://archive.ubuntu.com gutsy/restricted Packages
404 Not Found [IP: 91.189.88.45 80]
Err http://archive.ubuntu.com gutsy/universe Packages
404 Not Found [IP: 91.189.88.45 80]
Err http://archive.ubuntu.com gutsy/main Sources
404 Not Found [IP: 91.189.88.45 80]

Then this is your answer.

mysql> set global innodb fast=true;

Remember, this client is not a financial site, so the parameter of interest becomes innodb_log_flush_at_trx_commit. Setting this to 0 means that InnoDB will no longer flush every commit to disk. It will still do a flush every one second or so anyway, so in the worst case you may lose about one second worth of data. But on the other side, your disk is now freed up to do reads for you at full speed. The result — the site is fast again. Or, in the words of a user on the site: “OMFG someone fed the Hamster…the wheel is spinning again!”
via pythian.com

MySQL tuning is such a black art. This is a cool trick for non-financial sites that can tolerate small amounts of data loss.

Useful: How to migrate maildirs using rsync

rsync -av -e “ssh -c blowfish” –delete root@newserverIP:/var/mail/data/1* /var/mail/data/ &
rsync -av -e “ssh -c blowfish” –delete root@newserverIP:/var/mail/data/2* /var/mail/data/ &
rsync -av -e “ssh -c blowfish” –delete root@newserverIP:/var/mail/data/3* /var/mail/data/ &
via networkjack.info

We gotta move to a new mail server soon, so this will come in handy.