I do not know how memory allocation works on VMs so I get confused by this. My host has a total of 64GB RAM. However, upon calculating all my VMs inside, I have already assigned 90GB RAM in total. Does this means I already need to upgrade my physical RAM or transfer other VMs on a different host?
Asked
Active
Viewed 179 times
-1
-
2Want to give details on the platform and virtualization solution you're using? Maybe even the operating systems involved? – ewwhite Jul 18 '17 at 12:40
-
Hi. I'm using vsphere ESXI; IBM blade center s with 3 physical hosts inside. VMs are a mixed of windows server 2008/2012 and redhat Linux. – Faye Jul 18 '17 at 12:57
-
The scope of this question is too broad. Yes, you can overcommit RAM. – ewwhite Jul 18 '17 at 13:32
-
Sorry if its too broad. I just wanted to understand how memory allocation works in vsphere so I know how to correctly deal with its resources. – Faye Jul 18 '17 at 19:33
1 Answers
1
This is called memory Overcommitment in the terms used in VSphere documentation. It is safe as far as you are monitoring the memory usage of the host machine and confirm you have enough free pages.
Other virtualization solutions may or may not be similar, but I believe it should be OK since it already allowed you to configure it this way.
Khaled
- 36,533
- 8
- 72
- 99
-
How do I know if I should stop creating VMs already? Actually, one of the VMs here (Redhat Linux os with 32GBRAM) has already signs of CPU hang up and I am not sure if this overcommitment is the culprit because other virtual machines are still doing fine. – Faye Jul 18 '17 at 13:01
-
@Faye: You will start having troubles when you have no or very few free memory. – Khaled Jul 18 '17 at 13:04
-
What about reservations and DRS affinity rules? The answer to this question is probably more complex. – Greg Askew Jul 18 '17 at 13:05
-
@Khaled I think so too, maybe I should start making graphs of the daily usage of my VMs – Faye Jul 18 '17 at 19:34
-