How to increase the CPU entitlement percentage in HPVM

[senthil_kumar_1]

Hi All,

I have configured HPVM on HP Integrity server "rx3600"...This server is having two dual core CPUs...

Right now I have configured some VMs..

# hpvmstatus -r
[Virtual Machine Resource Entitlement]
[Virtual CPU entitlement]
                                                                     Percent                                                 Cumulative
Virtual Machine Name VM #  #VCPUs Entitlement Maximum   Usage            Usage
====================      ===== =========    ======       ===== ==========

systemhpvm01             3      2               10.0%         100.0%    0.0%                0
systemhpvm02             5      4               10.0%         100.0%    0.0%                0
systemhpvm03             6      2               10.0%         100.0%   40.6%        272273367
systemhpvm04             7      4               10.0%         100.0%    0.0%                0
systemhpvm05             8      1               10.0%         100.0%    0.0%                0

My Questions:

1)I can have maximum 400% CPU entitlements for all VMs as I am having 4 pCPUs (two dual core CPUs), Am I correct?

2)Right now I have assigned 130% CPU entitlements for VMs, Am I correct?

3)How to increase the CPU entitlements on "systemhpvm03" and how much we can increase?

[Dave Olker]

Hi,

In answer to your questions:

1) Yes, you can assign up to 400% CPU entitlements but you need to take care in how you do this because you could potentially get yourself into a situation where you cannot start all of your guests because of the way the entitlements consume CPU resources. This is a topic I covered in my "Integrity VM Performance Best Practices" session I gave at this year's HP Discover Conference. Seeing the animated slides make explaining this much easier. :)

2) Yes, the current configuration is specifying 130%. However, that is just the guaranteed minimum entitlement - when the VM is busy. You also have each guest configured to use 100% entitlements for their respective CPUs. What does this mean? Any of the guests can get 100% of the CPU they are running on if they are the only VM guest requesting resources. If the other guests are idle, they can give up their entitlements - even below the guaranteed minimum 10% - and allow the guest requesting resources to consume them.

3) Why do you need to increase this guest's entitlement at all? It's currently using 40% of the 2 cores it runs on and it can potentially use 100% of those cores if the other guests are not using them.

I typically recommend to customers to use the default entitlements and let the scheduler assign resources on an as-needed basis. Looking at your example, 4 of your VMs appear idle which means the active VM (03) can potentially use 100% of the 2 CPUs it is configured to use. If the other guests start running workloads and need their 10% entitlement back they will get it. Depending on how busy vm03 is, it might get it's CPU allotments cut back and it might not. If there is still spare capacity on the CPUs then vm03 may be able to continue using it's extra resources (above the 10% minimum entitlement) and still allow the other VMs to get their 10%.

I hope this helps.

Dave