[xwiki-users] monitoring tools?

Hello XWiki users, I'd like to know what the users of XWiki use as monitoring tools. Does anyone have experience with Nagios? Zabbix? AlertSite? Another? A hand-made solution? (I haven't met one that is java based, that'd be cute!) Here's my answer: - with i2geo.net, we used Nagios, it was relatively faithful at warning of downtime and even at warning "failed restart" (which remain a mystery to me but happen, from time to time) - with curriki.org, we use AlertSite, it works very well to warn about the downtime and plot performance changes. Internally, also, we use a script to detect too long response times and restart (which happens when queries start to lock too many other queries) and a hand-made monitoring tool which displays a synchronized overview of the top, page loading time, apache and appservlogs, and mysql queries; it's a youngish but can help diagnose. thanks in advance Paul