vReference » HA http://www.vReference.com guides, links and news for VMware and virtualization technologies Tue, 31 Jan 2012 15:54:43 +0000 en hourly 1 http://wordpress.org/?v= n+1 is hogwash! http://www.vReference.com/2010/02/15/n1-is-hogwash/ http://www.vReference.com/2010/02/15/n1-is-hogwash/#comments Mon, 15 Feb 2010 15:03:31 +0000 Forbes Guthrie http://www.vReference.com/?p=687 Too frequently I hear the expression n+1 as a model for ESX clusters to provide High Availability.  If you EVER expect to patch ESX servers without VM downtime then you need at least(†) n+2.  When running your clusters to only n+1, you can never safely put one of your hosts in Maintenance Mode; not if High Availability is important [...]

===== n+1 is hogwash! originally posted by Forbes Guthrie on vReference. Subscribe to my RSS feed for all the latest updates, and follow me on Twitter for shorter ramblings.

]]> Too frequently I hear the expression n+1 as a model for ESX clusters to provide High Availability.  If you EVER expect to patch ESX servers without VM downtime then you need at least(†) n+2.  When running your clusters to only n+1, you can never safely put one of your hosts in Maintenance Mode; not if High Availability is important to you.

Footnote: If you don’t understand the importance of HA slot sizes, go learn.

===== n+1 is hogwash! originally posted by Forbes Guthrie on vReference. Subscribe to my RSS feed for all the latest updates, and follow me on Twitter for shorter ramblings.

]]> http://www.vReference.com/2010/02/15/n1-is-hogwash/feed/ 3 VMworld: HA http://www.vReference.com/2009/09/05/vmworld-ha/ http://www.vReference.com/2009/09/05/vmworld-ha/#comments Sun, 06 Sep 2009 06:56:49 +0000 Forbes Guthrie http://www.vReference.com/?p=303 While attending the HA: Internals and Best Practices session (BC3197) on Tuesday afternoon, I learned something new about HA’s VM health monitoring.  With a cluster’s HA, you can set it to monitor the health of your VMs and have them automatically restart if it detects an OS hang-up.  To do this it uses a heartbeat [...]

===== VMworld: HA originally posted by Forbes Guthrie on vReference. Subscribe to my RSS feed for all the latest updates, and follow me on Twitter for shorter ramblings.

]]> While attending the HA: Internals and Best Practices session (BC3197) on Tuesday afternoon, I learned something new about HA’s VM health monitoring.  With a cluster’s HA, you can set it to monitor the health of your VMs and have them automatically restart if it detects an OS hang-up.  To do this it uses a heartbeat from the Guest’s VMware tools.

The cool thing I never knew before is a screenshot of the VM’s console is taken before it is reset, with up to 10 being saved (in the same directory as the vmx file).  So when you are trying to troubleshoot the issue that caused the VM to become unresponsive, you should have a screenshot of the BSOD or any onscreen messages.  Cool.

===== VMworld: HA originally posted by Forbes Guthrie on vReference. Subscribe to my RSS feed for all the latest updates, and follow me on Twitter for shorter ramblings.

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