I’ve been working on an overhauled version of the HA Deepdive Page. I’ve been adding “basic design principles” which hopefully you find useful.Here’s an example of what they look like:
Basic design principle: For iSCSI the preferred isolation response is always “Power off” to avoid a possible split brain scenario.
Another bit I’ve added is the following:
Please [...]
Posts Tagged ‘ha’
Overhauling the HA deepdive section
February 23rd, 2010
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HA admission control, the answers…
November 9th, 2009
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I received a whole bunch of questions around my two latest posts on HA admission control. I added all the info to my HA Deepdive page but just in case you don’t regularly read that section I will post them here as well:
The default of 256Mhz when no reservations are set is too conservative in [...]
How to avoid HA slot sizing issues with reservations?
November 6th, 2009
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Can I avoid large HA slot sizes due to reservations without resorting to advanced settings? That’s the question I get almost daily. The answer used to be NO. HA uses reservations to calculate the slot size and there’s no way to tell HA to ignore them without using advanced settings pre-vSphere. So there is your [...]
Using limits instead of downscaling….
September 25th, 2009
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I’ve seen this floating around the communities a couple of times and someone also mentioned this during a VCDX Panel: setting limits on VMs when you are not allowed to decrease the memory. For example you want to P2V a server with 8GB of memory and an average utilization of 15%. According to normal guidelines [...]
HA: Did you know?
September 20th, 2009
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Did you know that…
the best practice to increase the isolation response time(das.failuredetectiontime) from 15000 to 60000 for an Active/Standby situation for your service console has been deprecated as of vSphere.
(In other words for active/standby leave it set to the default 15000 for vSphere)
the limit of 100 VMs per host is actually “100 powered on and [...]
Future HA developments… (VMworld – BC3197)
September 15th, 2009
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I was just listening to “BC3197 – High Availability – Internals and Best Practices” by Marc Sevigny. Marc is one of the HA engineers and is also my primary source of information when it comes to HA. Although most information can be found on the internet it’s always good to verify your understanding with the [...]
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