Before you attempt such an upgrade yourself, be sure to make a backup of your Linode. If you have enough diskspace left with Linode, the easy way is to resize the image that you’re using for your server and then duplicate it. Alternatively you can download a copy of the image (which can be quite time consuming, depending on the size).

The Linode manager makes it easy to use different disk images with your Linode, so if you mess up then you can switch to the backup image and revert to the situation before the upgrade. Kudos to Linode for offering such an excellent service with such excellent tools!