Is there anyway of checking if a host's "uptime guarantee" is true? Many places seem to promote uptime as one of their main selling features, but is there any way of actually checking how often a server/site is down? (apart from visiting it all the time, obviously)

well go to Google and search "free website monitor" and you will see many of the sites providing the service you actually need

Signup for a free Pingdom account. You can also ask the host to provide you with stats.

Be aware that many of the places that offer these ping services for free are only monitoring things every hour - so if a site was offline for 3 minutes, you may never know about it.

There's a few out there that do more frequent monitoring, and then also monitoring from multiple locations.

I like www.freesitestatus.com as they monitor from several locations and can monitor different services every minute. Runs at $12/month per URL monitored.

www.host-tracker.com is another popular place, to get into the 1 minute interval tracking range you're looking at about $30/month for up to 20 urls.

Pingdom has some great monitoring too.

their is also uptime robot, but these always produce false positives and even when you provide server logs showing that the server/sites were never down all you get from them is that their stations say the server/site was down, so it was down

Yep - we used to use UptimeRobot here on our servers for clients, but no longer use them. I remember when they first started, we had offered to provide server equipment for them as a donation to be able to help expand their network and monitoring locations, but the response from them was this was not a real company and was setup as a student project or something. At the time, the plan was to take things offline in August 2010, but I see things are still going with them - and still free.

As always, you get what you paid for. Sometimes spending a few dollars is worth the extra step of redundancy or reliability.

We swapped over to www.BinaryCanary.com back in 2010 and couldn't be happier with the reports and monitoring information. We now monitor hundreds of servers every minute and couldn't be happier with them!

We use 3rd party uptime tracking services to track and display known uptimes for servers and use them to keep in touch as to what is going on in our servers.

But setting the interval time to 1 minute can give false positives. Setting it to 5 minutes with Pingdom works fine for me. Can see page for example http://stats.hostxnow.com. I heard BinaryCanary.com is good too.

1 minute IS an issue for some people, but here's the deal with the interval.

You only get noticed when something has failed to respond 3 times - this eliminates the false positive. The problem however is that if you have it on a 5 minute interval, then that's 15 minutes of downtime BEFORE you ever get notified that there's an issue.

We have our own internal monitoring that is actually on a 10 second response time, so we know within 30 seconds if there's something happening and a ticket is opened and closed by the system. Even if it's a 30 second downtime, there's SOMETHING happening that should be investigated by an admin before longer outages happen.

The advantage with multiple monitoring locations is that if something is down from 3 different locations, then you really know that it's down, and not just down for one location.

Most you have to pay for every 1 minute and some every 15.

However there is loads online, google will bring them all!

The free service was great for a while, then features got worse and quality (at least for the free service) stopped being all that great.

I have found Pingdom to be very good. Also, I liked some of the advanced features of Wormly, though I imagine they're a bit much and not of much use to a casual hosting user, and anyone with root access has more advanced/reliable tools to rely on.

Host trackers beta works out $10.80 a year for a 1 minute interval on http. but you can only pay by CC/DD that allows recurring payments i tried with a paypal access mastercard and it failed as the card does not allow recurring payments