Enter a ESXi 5.0 into maintenance mode

[keshav_mukati]

i am in a situation, i have a cluster of 3 ESXi host, one ESX is running with 97% used memory and other 2 are with 70% used memory.

In this work load, can i put a host into maintenance mode successfully ?

And what are the risk to perform this activity, if i am able to put a host into maintenance and due to high resource consumption is there any risk of unplanned downtime ? VM crash ? Host Crash? etc..

Few of the Datastores are also 97%+ used.

[Alistar]

Hello,

if such a situation would happen, you would be forced to power some VMs off in order to satisfy the resource requirements for two ESXi hosts. Your choices are either to decrease some VMs' memory or to purchase new hardware. Datastores being this highly used is bad news as well, you will be facing serious problems once these numbers hit 100%. You can also oversubscribe the memory on ESXi a little bit but not to the point where they start swapping to the hard drive - that would be detrimental to performance.

If these ESXi host business (or worse, business-critical) applications, I'd recommend you to urge your managers to allow you purchase a new hardware or negotiate an upgrade.