Sometimes when you visit the site, it will return you a blank page or give you a null response back, for example:
$ curl –head lesterchan.net
curl: (52) Empty reply from server
I have still yet to figure out the problem yet. But it seems a simple Apache restart does solve the problem. I have about 2GB of RAM on this VPS server and I don’t think it is out of memory because I did check the RAM when this happens and it seems I still have more than 1GB available. Apache processes appears to be running as well. The last thing I installed on this server is XCache 1.3.1, I wonder if it has anything to do with it.
But anyway, I have been using Pingdom for a couple of years and it has a nice iPhone App that alerts you via Push Notification if your server is down. I have it check my site every 5 minutes.
I recently tried out WatchMouse as recommended by colleagues and it seems much better than Pingdom in terms of features and node locations. But it is a little expensive (cheapest is US$35 per month), considering I don’t earn anything from this site. There is a free account on it though, I just have to put up a small banner on my site (which I did on the right menu). The free account is good enough for me, they check this site once every 20 minutes for the free account.
The feature I like most about WatchMouse is the Public Website Health Status Page and it is available on the free account as well, check out, http://status.lesterchan.net/ (yeap, they even allow you to have CNAME). I have also set up a new Twitter account, @lcstatus which basically adds like a RSS feed for http://status.lesterchan.net/ (announcements section).
A WatchMouse Public Status Page enables your organisation to display information about the availability and performance of your critical services. You can post announcements, annotate current issues, and optionally set up a special host name (CNAME) so people can access the status page using your domain name, e.g. status.yourdomain.com. It is an easy control channel through which you can transparently inform visitors about the status of your sites and web services.
All WatchMouse Public Status Pages are hosted on Amazon’s Cloud infrastructure so they are available even if your site or service is not.