Host memory minimum for HA?

[rickardnobel]

The memory minimum for ESXi should be 2 GB of RAM, but I wonder if that is enough for running the HA Agent? On two test ESXi with 2 GB of RAM when trying to setup HA it failed and something from the error messages made me suspect lack of RAM. After adding up to 2.5 GB of memory HA went through.

So my first question is: any minumum amount of RAM on a host for HA to work?

On the same cluster with these two small ESXi servers I noticed that the slot size was about the expected, something like 256Mhz and 360 MB of RAM. HA setting = tolerate 1 node and small VM running only. What was quite strange to me was the the Advanced Runtime Info reported only 1 single slot in the whole cluster and when doing a HA test with power off one host the VM did not fail over and HA reported "not enough resources to failover VM" or similar. Why could this be happening? Does HA expects more RAM to be available?

[admin]

Can you upload a screenshot (or the data) of the advanced runtime info pop-up? Which version of VC are you using? From the "resource allocation" tab of the cluster what is the "total capacity" and "available capacity" for cpu and memory?

Elisha

[a_p_]

So my first question is: any minumum amount of RAM on a host for HA to work?

I can't tell you where to find an official documentation about this, however the minimum RAM to be able to configure HA is something between 2.3 and 2.4 GB RAM.

André

[rickardnobel]

Can you upload a screenshot (or the data) of the advanced runtime info pop-up?

Thanks for your reply! I will upload a screenshot tomorrow from work.

Which version of VC are you using?

It is vCenter 4.1.

[chriswahl · Accepted solution]

HA requires 2300 MB of memory to enable. If you have less than this amount, you will get an error when trying to enable HA.

[rickardnobel]

Chris Wahl wrote:

HA requires 2300 MB of memory to enable. If you have less than this amount, you will get an error when trying to enable HA.

Great, I have not seen that number before. (And of course it is kind of unusual with such small servers these days, but the minumum is still 2 GB)