Comments on: vSphere 4 – System Resource Allocation/Reservation

By: Yzel20

Yzel20 — Sun, 13 Jun 2010 20:27:46 +0000

what is resource system management?

By: Jeff Adams

Jeff Adams — Thu, 03 Jun 2010 20:10:07 +0000

Simon,

We use vRanger too, and yes, this is a recommendation from Vizioncore.

vRanger Pro 4.5 Deployment Guide
http://vizioncore.com/products/vRangerPro/docum...

Page 33-34.

During standard backup operations, the ESX Service Console is used to run vRanger
Pro backup tools. The additional performance load placed on the Service Console
should be addressed by implementing the suggestions below.

Service Console Configurations

Vizioncore recommends that the two changes below are made on your ESX hosts to
optimize the regular backup of VMs. These ESX resource reservations are not
mandatory and recommended only for operation efficiency.

• Increase the Service Console CPU Reservation to 1500 MHz

In the VI Client inventory, select the ESX host > Configuration tab > System
Resource Allocation. Click the Edit link and adjust the CPU reservation slider up
to 1500 MHz.

• Increase the RAM allocated to the Service Console to 800 MB.

In the VI Client inventory, select the ESX host > Configuration tab > Memory >
Properties and then modify the amount of RAM from the default of 272MB up
to 800MB.

Note This will require a restart of the ESX Server.

-Jeff

By: Tom Howarth

Tom Howarth — Wed, 19 May 2010 22:02:47 +0000

To be fair, I can not really add anything to the conversation, my ESXi experiance is next to none existent, however personally I would think that there would need to be some reservation as there are still management tasks and overhead of the VMKernel Management interface to consider.

By: anil345

anil345 — Wed, 19 May 2010 02:04:01 +0000

Simon – In reply to your followup question.

For me – It really depends on how the VM environment is setup and being used for… our environment has spare resources and DRS is not hyper active all the time. However, we do run quite a few backups during day time and some of them are time consuming because of the server sizing etc.

If our environment was highly dynamic in the sense of vMotions occuring all the time, VCB backups running, and so on i would actually be interested to increase the reservation a little more than what i have reserved right now. I have seen definite improvements (statistically) by making these changes.

By: Simon Long

Simon Long — Wed, 19 May 2010 01:43:07 +0000

Its a Rabbit Hole! Good fun though.

By: Virtualpro

Virtualpro — Wed, 19 May 2010 01:35:52 +0000

I've just read through Frank's article mentioned above. Sometimes you think you've understood what exactly is happening but there seems to always be another layer of complexity lying just underneath )

http://frankdenneman.nl/2010/05/resource-pools-…

By: Simon Long

Simon Long — Wed, 19 May 2010 01:22:53 +0000

Hi Massimo, I don't think I made my point very well in my post, for which I apologise. I'm specifically talking about the System Resource Reservation on a Host itself. If you see the screenshot above, that is displaying the advance view of the Resource Reservations.

It seems by default, the host in the screenshot has a CPU reservation of 221MHz (Not set by anyone), but the Memory reservation is 0MB. I'm interested in that. Is it best practice to add a value to this to reserve some memory resource? If so how much?

I was also asking if anyone actually change any advanced settings, but its seems as though it's not a good idea to go there.

And thoughts?

Simon

By: Massimo Re Ferre'

Massimo Re Ferre' — Wed, 19 May 2010 01:10:31 +0000

Simon, I think one of the things to consider is that you dont' set Resource Pools to “tune” your setup or to make it run smoother. You set Resource Pools to segment the workloads and share the infrastructure among different tenants (to which you delegate the usage of those resources). So you'd want to use them if you are allocating/reserving cpu-cycles and memory for the HR department, for the sales department, for the RD department and so on. If you, as the sysadmin, has a flat view of your internal/external customer base I dont' see a reason why you would want to play with RPs. On the other hand if you want to create a multi-tenant infrastructure where customers buy a certain amount of resources and deal with those resources (i.e. delegating them) then RPs come very handy.

I manage to say that RPs are key to a cloud-like deployment w/o ever mentioning the word cloud. I am improving

Massimo.

By: Simon Long

Simon Long — Wed, 19 May 2010 01:02:34 +0000

Hey Frank, thanks for the Link and Gab, I've never heard that one before..I like it though.

It was part of our companies build document to always make sure Service Console had 800MB Reserved. Now we are using ESXi, I decided to find out exactly what we needed rather than just set a value that someone decided back in v3.x days. So far it seems as though people are just leaving as-is unless instructed to change it by a 3rd-party app vendor.

Would it not be a good idea to reserve some resource to as a fail-safe? In case for some reason the Host became heavily over subscribed, there would still be resource to manage the Host to fix the issue? If it's as easy as putting 500MB in the “Simple” Memory Resource Reservation, why not do it? or do I have the wrong end of the stick and this Resource Reservation is for something different?

Simon

By: Simon Long

Simon Long — Wed, 19 May 2010 00:52:57 +0000

Hey Anil, if you weren't running a 3rd party app, would you just leave them as default?

Simon