Comments on: Memory reclamation, when and how?

By: jitesh

jitesh — Sat, 11 Jun 2011 12:55:23 +0000

hi frank

since esxi does not have a service console how does the 6% high memory state of the host work?
As you wrote “6% of the ESX host physical memory minus the service console memory must be free”
Does esxi use a different calculation?
Thanks

Jitesh

By: VCAP-DCA Study notes – 3.1 Tune and Optimize vSphere Performance | www.vExperienced.co.uk

Sat, 16 Apr 2011 11:33:03 +0000

[...] Read this great series of blog posts from Arnim Van Lieshout on memory management – part one, two and three. And as always the Frank Denneman post. [...]

By: VMware vSphere: Manage for Performance Course Experience « TheSaffaGeek

VMware vSphere: Manage for Performance Course Experience « TheSaffaGeek — Mon, 21 Feb 2011 15:24:45 +0000

[...] environment. Yet again Frank Denneman has covered these topics brilliantly in two blog postings Memory reclamation, when and how? and Disable ballooning? which I’ll personally be rereading through myself so as to better my [...]

By: Frank Denneman

Frank Denneman — Mon, 29 Nov 2010 13:37:24 +0000

Paul,

I’ve published a new article based on your question: http://frankdenneman.nl/2010/11/disable-ballooning/

By: Disable ballooning? | frankdenneman.nl

Disable ballooning? | frankdenneman.nl — Mon, 29 Nov 2010 13:33:38 +0000

[...] Paul Meehan submitted this question via a comment on the “Memory reclamation, when and how” article: Hi, we are currently considering virtualising some pretty significant SQL [...]

By: PPM

PPM — Fri, 26 Nov 2010 11:30:11 +0000

Hi,

we are currently considering virtualising some pretty significant SQL workloads. While the vmware best practices documents for SQL server inside vmware recommend turning on ballooning, a colleague who attended a deep dive with a SQL Microsoft MVP came back and the SQL guy strongly suggested that ballooning should always be turned off for SQL workloads. We have 165 SQL instances, some of which will need 5-10000 IOPS so performance and memory management is critical. Do you guys have a view on this from experience ?.

Thx,
Paul

By: Top 5 Planet V12n blog posts week 23 | Download VDI Solutions

Top 5 Planet V12n blog posts week 23 | Download VDI Solutions — Wed, 27 Oct 2010 00:01:05 +0000

[...] Denneman – Memory Reclaimation, When and How?Back to the VMkernel, in the High and Soft state, ballooning if favored over swapping. If it ESX [...]

By: ML

ML — Thu, 21 Oct 2010 07:48:29 +0000

Hello,
I read the KB 1021896. It says :
In addition, if memory becomes over-committed on the system, the vmkernel and vmm can break large pages as necessary.
It could be interresting to consider this in this blog.

Do someone know if ESX use ballooning and page break simultaneously. Or try to break the pages, then use ballooning.

Regards

By: PiroNet

PiroNet — Wed, 15 Sep 2010 11:01:30 +0000

Hi Frank,
Are the Free Memory state’s thresholds (6%, 4%, 2% and 1%) hard coded or can be changed?
Thx,
Didier

By: YP Chien

YP Chien — Fri, 02 Jul 2010 17:07:51 +0000

Hi Sean:

You mentioned:
“Did you ever try VMotion-ing the ballooned or swapped VMs from overcomitted resource pool to resource pool with ample resources? If so did balloon driver stay inflated and swapped memory stay swapped? My guess is “yes”.”

Our tests were not done “deliberately” on ESX cluster with DRS so we could force memory balloon and swapping activities. With DRS, the VMs will be vmotioned to another ESX and I did find out that:
- Balloon memory will be gone
- swapped memory stay swapped and will be backed out to physical memory eventually
So to answer your questions, do take advantage of DRS to balance the workload. Memory balloon will only be deflated if:
1. all swapped memory has been backed out into physical memory
2. there are memory requests generated by the affected VM