On Friday the first ad went into the paper listing a page on this refreshed server, and of course the server crashed with the message “Cannot contact database”.
Caution: Technical mumbo-jumbo follows
The MariaDB server backing the wordpress application ran out of both memory and swap space, and crashed ignominiously.
Turns out, the default swap space allocation for this server was only 500Mbytes. Normally, you allocate the same amount of swap space as you have physical memory, though this is really a judgement call every time.
Luckily the good folks at linode.com have a very easy system for allocating storage space between swap space and file system space. I resized both (it’s not like we have hundreds of GBytes of files to store) and now this server will not crash under heavy load. It will swap, it will thrash, but it should not crash.