Will an Uptime Monitor Pick Up This Error?

[PaulPA]

I run a Joomla site with a good amount of traffic for its niche but I do not run it as a full time operation so there are times during the day when I do not look at the site for several hours. Yesterday was a bad day not to look at the site as it essentially went down from 10 am until I noticed it not functioning correctly around 5 pm.

Because it does generate revenue, I am thinking about using an uptime monitoring service of some kind. However, while I see this as being useful to alert me if the site is not accessible at all, what happened yesterday is a little different. For some reason the Joomla session table crashed and when you went to the site a message displayed indicating there was this problem.

My questions is would a monitoring service really view this as the site being down since, in effect, a page did load, granted with an error message? If monitoring services are capable of doing this, would most all monitoring services do this or should I just look for certain types?

[mylhat]

It depends on the monitoring service. Most free monitoring services monitor only if an ip pings, if a proper response code is returned(200, etc), or if http is accepting connection. These services probably won't catch the error.

Some monitoring services do something called string based monitoring. In string based monitoring, the monitor pulls the monitor page and checks it for a string. If the string is present, it either alarms or passes depending on the test.

For example the search string is copyright and you pass if it is found. If the page loads the footer that contains copyright, it passes. If there is a server error and the error message doesn't contain copyright or it white screens, it fails and alarms.

A different example is the search string failure and you want to alarm it is present. If you have a test page, you have it run a couple of test( can i connect to mysql, write a file, is there enough diskspace, etc) then print success. If not print failure and it will alarm. This is good for running multiple tests and having it alarm if only one fails but things like static pages works. I've seen people setup scripts to check server load and fail if is to high or disk space too low to alert someone of a possible future problem before it becomes a issue.

You probably want to try a monitoring service like this.

[PaulPA]

Thanks. Yes, the 200 code was appearing so it looks like those type of services won't help with this problem. I'll check into those other options.