Need Help in Configuration of Vmware Memory Ballooning

[ckiran04]

Hi,

We are using vmware vcenter 5.1 . We have around 500 VM's in our DC.

Most often we re running out of high CPU usage on our VM's. Overall Performance on Ops-manager is saying we are wasting a lot of memory.

I think we can solve this problem by using memory Ballooning.

Can some one please help me how to start.

We have not configured any resource polls in our env.

[a_p_]

Ballooning is automatically used as one of the memory saving techniques if VMware Tools are installed on the virtual machines. There's actually nothing you need to configure manually.

André

[rcporto]

If vCOPs says that you have a lot of waste memory this means that some VMs are oversized and the solution is reclaim the memory from this VMs, not through ballooning (vSphere already do this automaticaly if needed) but adjusting the amount of allocated memory for the VM.

[ckiran04]

Thank you for reply rcporto,

I am confused to how to start. can i reclaim resources with out down time. and also  please suggest me some best way of configuration of ESXi hosts in cluster.

Actually i am new to this. I am confused how to start this.

[macvirtual]

Hi,

I think it's not good idea to user Memory Ballooning to reclaim unused memory. Since, actually I faced ballooning works by mistake once, it was literally "nightmare".

The memory ballooning requires lots of CPU resource and that often cause VM slow down. So memory ballooning is not for usual operation to resolve memory imbalance, it should use only to resolve serious resource starvation. So, the first step to ensure your DC performance is review your VM sizing as rcport mentioned above. Make your DC VM density more high and tune memory tax parameter.

Best,

MAC

[wila]

ckiran04

My apologies for being blunt and stating the obvious, but ...

ckiran04 wrote:

We have around 500 VM's in our DC.

Actually i am new to this. I am confused how to start this.

Don't touch anything, go to your boss and demand a course for administering vSphere.

Without that you will break things and will be learning at the expense of the end users.

--

Wil

[TomHowarth]

you say you have 500 VMs running in your environment, but do not mention number and size of hosts, average size of VM.

you really do not want to be invoking ballooning in your environment, if you think your performance is bad now, then you will be in for a whole world of pain if you start to Balloon.

ESXi only starts to utilize memory managment during periods of heavy congestion.  also just because Opps Manager say that you have lots of wasted memory does not mean this is a bad thing.

your VMs may actually need the memory that has been assiged to function correctly at certain times of the months say month and year end.

I would start by looking for the more obvious memory hogs, things like reservations.  this is where a VM has been configured to grab a set amount of real memory at startup and will never release it.

Aso look at the Guest themselves does that server really need 8GB of memory just to service file and print.  also how many of your guests are multi CPU.  the vast majority of IT programmes still cannot take advatage of multiple CPUs,  just because a machine had 2CPU and 4 cores in each one does not mean it needs 8vCPU's in the virtual world.

just because your Guest had 16GB of phyiscal RAM in the phyiscal world does not mean it has ever utilised this.