NerdKey

Powered by NerdTools.co.uk Uptime Tracker (http://uptime.nerdtools.co.uk/) this plugin will add a widget to your sidebar that will show the percentage of availability or uptime for any website over the last 30 days.
In terms of the tracking system, checks are carried out every 5 minutes from different locations and then averages are worked out to form the overall reports from which the graph is generated and shown via an iframe.
Other reports including hourly, weekly and daily can be seen by visiting the Uptime Tracker website directly.
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Uptime Widget

Adds a simple uptime gauge to your WordPress sidebar, showing the percentage of availability for any website over the past 30 days.

Pingmeter

You might have a great website, shop or blog. so do your competitor. And they get your visitors when your site is down. It is stressful to have your website down and you get aware of it few hours after your visitors. Be the first one to notice.
Pingmeter ping your website constantly to ensure your website is working fine and take note of ping response speed. If your website timeout or go down, Pingmeter will double check it with our other servers across america, europe, russia and even australia, then notify you via SMS, email or even voice call on your phone.
Monitors can be associated with your website, so Pingmeter keep track of number of online visitors on your websites. and If a monitor go down, it notify you in call about number of your online visitors and record how many online visitors were on your website when this downtime happened.
Pingmeter monitor can scan HTTP, HTTPS, SSL Certificate validation, FTP, SMTP, POP3, IMAP, ICMP, MySQL and custom port pings. Monitors can be parents of a previous monitor, so for example you do not receive multiple alerts if your server go down and bring down HTTP, MySQL and FTP along with it.
Additionally, it can trigger pre-defined rescue actions to automatically recover your website such as modifying your CloudFlare DNS to your backup server or restarting your MySQL, Apache or other services by sending SSH command to your server.
Pingmeter give you a public (or private password protected) status page which you can link on your website so that your visitors can check your service status.
<h4>Read More:</h4>
http://www.pingmeter.com/

Pingmeter Uptime Monitoring

Pingmeter monitors and auto rescues your website during downtimes, so you can relax and focus on what's important. You can configure it to receiv …

Uptime Widget vs Pingmeter Uptime Monitoring