Ressource Pool reservation

[vSohill]

Hi ,

Base on what max reservation is 12,11 MHZ?

And why the capcity is 12.12GHZ when is the total CPU in the  cluster  is 40 GHZ

[vXav]

The max reservation you see is 12,119MHz or 12GHz ish.

Do you have other reservations set up? You can't reserve more than the cluster's resources minus existing reservations and (I believe) admission control's policy requirements.

[vSohill]

Thank you xXav

If I created 3 RP without any reservation does each RP will have the same capacity ?

[vXav · Accepted solution]

By default yes.

When you set a reservation, the cluster makes its calculation like if the reserved resources were used. If you set a reservation it means you want this resource available at all times even if the host is catching fire.

If expandable is checked, a consumer of a resource pool can "borrow" (up to its limit if one is set) from the parent resource pool if it has free resources.

If you don't set any reservations the full resources of the cluster will be used to calculate the entitled resources.

When Resource contention occurs (CPU at 100%) the shares will kick to distribute the resources to the VMs:

Example 1:

Root resource pool (cluster) : 40 GHz

RP A : Shares = 2000 (default "Normal")

RP B : Shares = 2000

So 50% each

RP A gets 20GHz

RP B gets 20GHz

Example 2:

Root resource pool (cluster) : 40 GHz

RP A : Shares = 1000 (default "low")

RP B : Shares = 4000 (default "high")

So 25% for A and 75% for B

RP A gets 10GHz

RP B gets 30GHz

Note that resource pools should only be used for resources distribution and prioritisation and never for organisational purpose, this is the job of the folders.

It's in a nutshell, I recommend you very well explained articles by Duncan Epping :

Resource Pools and Shares - Yellow Bricks

Shares set on Resource Pools - Yellow Bricks

[vSohill]

Thanks a lot vXavvXavvXav

Two questions more:

1- How can Active CPU more than Consumed ?

2- Is there any reason for not using RP as an organization container ? When VCD using RP as OU in vCenter. Is there any added overhead to the DRS ?

[vXav]

1- VMware vSphere 4 - ESX and vCenter Server

It's old but still applies.

2- Yes, RP should be used to manage resources.

I've never used VCD so I don't know how it works but you'd better use VM folders as "organisational containers".