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Even more on Fault Tolerance from the blogs

And the first cycle of our contest closes with these blog posts:

Eric Siebert – Master's Guide to VMware Fault Tolerance. Eric provides a comprehensive look at FT, tools to check the compatibility of your hardware, tips & best practices, and a list of links to further resources and his previous articles on FT. This is an article you may want to bookmark for future reference.

VII. So should you actually use FT? Enter SiteSurvey

Now that you’ve read all this, you might be wondering if you meet
the many requirements to use FT in your own environment. VMware
provides a utility called SiteSurvey
that will look at your infrastructure and see if it is capable of
running FT. It is available as either a Windows or Linux download and
once you install and run it, you will be prompted to connect to a
vCenter Server. Once it connects to the vCenter Server you can choose
from your available clusters to generate a SiteSurvery report that
shows whether or not your hosts support FT and if the hosts and VMs
meet the individual prerequisites to use the feature.

You can also click on links in the report that will give you
detailed information about all the prerequisites along with compatible
CPU charts. These links go to VMware’s website and display the help document for the SiteSurvey utility, which is full of great information, including some of the following prerequisites for FT.

Brian Atkinson – VMware Fault Tolerance Requirements and Limitations. Brian gives us a list of tips & considerations for FT brought together from a number of places.

This blog entry continues to get a lot of hits, so I thought I would
keep it updated and reformat it a bit. VMware's Fault Tolerance is a
great feature that has generated a lot of interest, and it is also a
new feature of vSphere that will only continue to improve. With that
being said, the list below is the current state of requirements and
limitations for enabling FT virtual machines in vSphere. The majority
of this information came from the vSphere Pre-requisites Checklist, the VMware Fault Tolerance Datasheet and the Availability Guide. Other items were picked up in the forums or in the VMware knowledge base. kb article 1010601 "Understanding VMware Fault Tolerance" is a great kb resource to start with, if you are new to this feature.

David Strebel – VMware Fault Tolerance Setup and Best Practices hits the FT highlights for a quick overview.

Here is a few of the best practices VMware recommends when using Fault Tolerance

  • Use multiple NIC’s, HBA’s etc. for redundancy
  • Isolate vMotion and FT Logging traffic
  • Use consistent power management settings
  • Limit the number of FT VM’s on a host to four
  • Use 10Gb NIC for FT logging
  • Synchronize guest OS time
  • Use NTP on ESX servers

Barry Coombs – VMware FT gives his perspectives, some use cases, and a very nice screenshot tutorial for how to use FT. 

There are already numerous white papers and technical documents
surrounding VMware FT so I didn’t want this just to become a rewrite of
one of these, I thought I would share some use cases that I have
experienced over my past few months installing vSphere, some findings
to help you getting started and a step by step overview of enabling FT
on your VM’s.  The work I undertake is mainly in the SMB environment so
this will maybe give those that work mainly with Enterprise
environments another view and also will hopefully be useful to those at
all levels of are considering or wanting to know more about VMware FT. …

I have recently completed a project for a legal firm, their Exchange
server was at the heart of their business and any downtime during the
limited amount of time their barristers have to access email could be
extremely costly. Although VMware HA would cover their risk of server
failure, they couldn’t afford to trust an unclean power down and the
amount of calls to deal with whilst the servers were booted on another
host would be huge. With only 2 IT staff managing their IT
infrastructure learning, monitoring and maintaining a complicated
replication or clustering technology would not be possible. So after
viewing a demo of VMware FT it was clear this was a must have feature
for them. After initial analysis and ensuring their Exchange server
could work within the limitations of FT their Exchange server was
virtualised and is now protected with VMware FT.

Didier Pironet – To FT Or Not To FT? asks himself the following questions with respect to VMware HA, VMware FT, and Microsoft clusters

You need to ask yourself the right questions:

  1. How long can I afford a downtime?
  2. How complex my high availability setup can be?

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