ESXi 6 TPS

ah, Transparent Page Sharing....I'm surprised this has not reared it's ugly head before on Experts Exchange, how VMware decided to disable this function by default with the release of ESXi 5.5 Update 2d,and not really tell many of us!

and this was due to a very low risk security concern, that VMware decided to turn if OFF  by default.

Many of our Clients have re-enabled this now, because it does help, especially with oversubscription e.g. it does save memory.

After the patch we have seen 200GB in shared pages, which have resulted in memory contention issues. (on some workloads, so the savings are different per host, cluster and environment)

It is believed to be low risk see here

https://kb.vmware.com/selfservice/search.do?cmd=displayKC&docType=kc&docTypeID=DT_KB_1_1&externalId=2080735

Here is a tool you can use, to check if you still have enough memory, if it's disabled versus enabled!

http://www.running-system.com/still-enough-host-memory-inter-vm-tps-disabled/

So in response to your question.

1. Yes we have enabled it. (The business considers it low risk versus memory saved!)

2. It saved 200GB. (memory saved on this workload).

Otherwise you've just got to increase your budget and put more memory in hosts!

Does the changes require a reboot?

It does not require a reboot,  but lots of options here to confuse you... because since it was disabled, they are no various different options based on Host version, and salting!

see here

https://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=2097593

IN the following article what does the term memory sharing between VMs with the same salt mean?

https://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=2097593