We have a Drupal 4.5 site running on a Pentium 4 with 1GB RAM (shared with other sites: one Drupal 4.5, some WordPress, some MT) and it might be that Drupal has been responsible for hanging it several times. The server gets collapsed and the only solution is to restart it - the hard way.
(Ruby On Rails was the suspect so we move it to another server, but now it has happened again)
The site < http://www.popmadrid.com > is a music community/ecommerce site [1], with two vocabularies (bands and labels) with +700 (seven hundren) terms each (being this huge vocabs the new suspects...). And not much traffic: 1200 users daily and 5000 page views.
We activated the MySQL logs (general and slow) since last time and this morning the server crashed again. So we have fresh material to look at :)
But it shows nothing strange :( (or at least something I can't get a clue from)
At 7:55 this morning mysqlslow starts to get fillep up with slow querys from the DB Drupal is running on (and some querys from another apps). They are normal Drupal querys from core modules - The first query start at Query_time: 6; with many querys each second. Gradually (for 3-4 minutes) querys starts taking more time, 10-20, until some peaks of 120-130 query time and then query times between 40/60 and 100/150, with some very huge UPDATE cache SET data in the middle, until 8:25.
At 8:24 with get query times of 400 up to 1200 at 8:35, the time at which messagges log stopped loggin anything. mysqlslow kept logging querys up to 2000 query time until we restarted.
Some hint of what might be happening?
ciao álvaro