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EpicFailover

EpicFailover is the automatic failover system designed for Tomcat and JBoss and provided free of charge on all Metawerx hosting plans.

Current version: 1.42

Table of Contents

Introduction


What is it?

  • Advanced monitoring and failover for your website
  • Instead of seeing a browser error when your VM is offline, users accessing your site will be directed to our failover device

When is it used?

  • Automatically when your JVM is offline: during maintenance, manual restarts from SiteWinder, or monitor-initiated restarts whenever there is a problem detected with your JVM by our monitoring software
  • Manually on demand: when you want to temporarily take your site offline (eg: starting a large hibernate application)

Benefits


  • Your website never appears "offline" to your users during JVM restarts or maintenance
  • Users are reassured that you are in control of the situation and that the website will be available again shortly
  • It's automatic
  • It's simple
  • It's free for HTTP! (SSL-based failover requires an additional dedicated IP address if you want your own SSL certificate served up)

Ideas - Making the most of maintenance periods


  • Maintain your visitors' attention during temporary outages by providing specials, deals, or articles on your Failover Page while your JVM restarts
  • Provide users with a discount coupon for use in your online-shop on your Failover Page, turning any disruption of services into a benefit for the user and increasing their chance of making a purchase
  • CMS operators and Resellers - create custom Failover Pages for each of your customer domains

Types of Failover


Automatic Metawerx Default Failover Page

  • Free - active now on your VM
  • Our default page has been activated on your account already, and features a standard message explaining what is happening, automatic reload, a countdown timer, and shows the page generation time. Realistically, it's rather boring, but it does the job well and displays on all browsers, Android, iPhone and most other mobile devices.
  • Since a Customised Failover Page is free of charge, we recommend you create one of those instead! Simply send us a URL from your website!
  • Click here to see the Default Failover Page

Customised Failover Page

  • Free - send us your URL
  • You can include images, CSS, JavaScript, movies, etc..
  • You can also have a page displaying products from your database, reviews, articles, a movie, or anything you like.
  • See the Ideas section for some tips on how you can take advantage of a useful Failover Page!
  • We will snapshot your page directly into our failover device, including all dependant resources

Full Automatic Failover/Failback to secondary JVM

  • This option requires an additional JVM on your hosting plan
  • Choose from a discounted low-usage secondary JVM, or a standard-size secondary JVM for load-balancing
  • Failover to the secondary JVM and Failback to your standard JVM is free of charge and automatic

Detailed Features List


Automatic

  • Failover is initiated in under 2 seconds by Metawerx Monitoring if your JVM process is not running
  • Failover is initiated in under 60 seconds (to allow for false positives) by Metawerx Monitoring if your JVM process does not return a standard HTTP response, or the text you have specified in the first 10k of the response
  • Your JVM resource usage and logs are scanned every 5 seconds by Metawerx Monitoring until JVM is responding again, then requests are switched back to your JVM

Manual Control (coming soon)

  • Manually take your website offline when performing upgrades, without appearing to be "offline" to your users

Instant Failover

  • The time taken to switch to maintenance-mode is under 40ms
  • A new instance of your JVM is started on our HA-Cluster in under 2 seconds
  • Your maintenance page will be displayed until your system is responsive again
  • You are alerted on all failed startups or successful startups

Instant Resume

  • Caching is disabled to ensure the Failover Page is not cached as the real website in browsers or proxies, and that your real website appears as soon as Maintenance Mode is disabled
  • Connections are closed on the Failover Page output to ensure a Refresh or Reload connects to your real application when it's ready
  • When our monitoring systems notice your website is back up, failback (resume) is initiated and completed in under 40ms
  • Using Metawerx monitoring, with 14 years of experience in Java monitoring, we check a combination of your JVMs open network ports, logs and CPU usage to determine whether your JVM is ready to efficiently serve requests again. Recent improvements in our monitoring have resulted in a 20-50% reduction of startup times for some JVMs when using failover, especially shared JVMs and JVMs using Hibernate.

Search Engine Friendly

  • A 503 (Service Unavailable) status code to temporarily block Google and other indexing systems, while still showing a normal webpage to your visitors
  • A Retry-After header is sent to specify that search engines should retry after 2 minutes
  • The new Google/Yahoo compliant X-Robots-Tag header to prevent Google and Yahoo from indexing the Failover Page

Simple and Flexible

  • Works with any existing URL in your application, so it doesn't matter what page the user requests after Maintenance Mode is activated
  • You can use the standard Failover Page from Metawerx or your own fully customisable page, directly from your website

Consistent Look and Feel

  • Your Failover Page can have exactly the same look as the rest of your website
  • We can "snapshot" an existing URL, so you can use images, CSS, javascript, standard HTML, or even output from JSP, Servlets, Struts, CMS systems or other Java applications

Safety

  • A series of checks are performed before entering Maintenance Mode to ensure that it can be ended automatically when your JVM is back up (Metawerx Monitoring and failover/failback configurations are all checked)

FAQ - Frequently Asked Questions


How can I start using it?

  • You don't need to do anything, we have already activated this feature for all hosted Tomcat JVMs

How can I see what my Failover Page looks like?

  • Browse to http://yoursite:9080

How can I change my Failover Page?

  • Go to SiteWinder -> Domain Administration and click your domain name.
  • Enter a Failover URL, eg: /maintenance.jsp
  • Our failover device will scan this page and you can test that it looks correct by browsing to http://yoursite:9080

Can I access my real website when it's in Maintenance Mode?

  • Browse to http://yoursite:8080

Will I get notified when my site enters or exits Maintenance Mode?

  • We can arrange this feature on request
  • Standard policy is that you will be notified when your JVM has completed restarting, or if it cannot be restarted, to cut down on alerts

Coming Soon


SiteWinder features

  • Manual Maintenance-Mode control
  • Ability to automatically import your own Failover Page
  • Daily-Refresh mode to refresh your Failover-Page every day

See Also


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