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mhashemi
Contributor
Contributor

Removing memory reservation

I have a Linux device with a 6GB memory reservation. I want to remove that reservation, but need to understand what will happen to the running VM, when I do so.

The VM is using only ~3GB of memory now, so I assume the OS won't see anything happen. Correct? Thanks.

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Anjani_Kumar
Commander
Commander

Correct. But make sure you have enough free resources available to satisfy the needs for your VM.This memory reservation ensures that ur VM will not feel any resource constraint till what is configured for the VM.

Please consider marking this answer "correct" or "helpful" if you found it useful. Anjani Kumar | VMware vExpert 2014-2015-2016 | Infrastructure Specialist Twitter : @anjaniyadav85 Website : http://www.Vmwareminds.com
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Paltelkalpesh
Enthusiast
Enthusiast

Memory reservation is guarantee for access to physical memory for the virtual machine but remember every VM has swap file size is defined (configured memory-memory reservation).

when it comes to VM memory reservation settings, I recommended to power off VM to change memory reservation settings,

Every powered on Virtual Machine on the ESxi host will have a.vswp file (swap file ) associated with it. This .vswp file will stored in the Virtual Machine directory by default. This .vswp file will be automatically deleted, when virtual machine is powered off. By default, .vSwp file size is same as the configured memory size of the Virtual machine. This .vswp file will be used, if the host is actively over-committed and higly utilized.



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CoolRam
Expert
Expert

It's like you are removing the guarantee that VM memory you dedicatory reserved.

In previous case even when your VM not using this much memory but the memory will always reservered for that VM. Now it will not reservered for this VM.

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malleswar77
Enthusiast
Enthusiast

Hi,

Yes, If you remove the memory reservation to 0 mb, then the .vswp file will increase to size of the configured memory of the VM. But VM continues to run.

There will not be a memory guarentee for the VM.

If any memory contention happens then VM performance may degrade.

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