Really, this amount of overcommit is nothing. It's been done for decades.
I manage a little over 200 virtual servers, spread across 7 z/VM hypervisors, and 2 mainframes. They are currently running with overcommit ratios of 4.59:1, 3.87:1, 3.56:1, 2.05:1, 1.19:1, 1.19:1, and.9:1. And this is a relatively small shop and somewhat low overcommits for the environment.
That's one of the benefits of virtualization...and yes, I know that if all guests decided to allocate all of their memory at once, we'd drive the hypervisor paging subsystem up the wall. Actually, this did happen a few months ago and while everything was dog slow for a while, z/VM happily paged along with out issue.
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Really, this amount of overcommit is nothing. It's been done for decades.
I manage a little over 200 virtual servers, spread across 7 z/VM hypervisors, and 2 mainframes. They are currently running with overcommit ratios of 4.59:1, 3.87:1, 3.56:1, 2.05:1, 1.19:1, 1.19:1, and .9:1. And this is a relatively small shop and somewhat low overcommits for the environment.
That's one of the benefits of virtualization...and yes, I know that if all guests decided to allocate all of their memory at once, we'd drive the hypervisor paging subsystem up the wall. Actually, this did happen a few months ago and while everything was dog slow for a while, z/VM happily paged along with out issue.