ESX Host Memory Issue

[wardb0071]

Good Day,

I have a VM running Windows Server 2008 64 Bit With Exchange 2007.

I've Allocated 16 GIG of memory to the VM.

The host ESX is always using the full 16 Gig for the VM even though the vm it self rarely ever uses more than 8 GIG except during backup and optimization at 11 pm.

Any thoughts on why the HOST is always using the full 16 GIG?

Attached is a couple of screen shots of performance and config.

Cheers,

Brian

[weinstein5]

The screen shot you have attached of the VM is the settings for the VM - just because the limit is set to 16 GB does not mean the VM is using 16 GB - I would take a look at the memory perfomance graph for the VM and I think you will find it is using less than 16 GB and I will bet it will even be using less than the 8 GB the VM o/s says it is using -

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[wardb0071]

Actually it looks as though my VM is using the full 16 gig between 11pm and 9 am. (Attached screen shot)

I guess thats why people that start work at 7am complain Exchange is slow, then when

I come in at 9 it seems fine :smileyhappy:

Exchange must be doing some sort of maintenance during that time, as noone is using the systems during those hours.

[geddam]

I would appreciate if you can provide more information on this....

1. What is the Exchange role you have configured on this box?

2. Is this VM clustered with any other VM or physical host or is it a standalone VM?

3. Seeing what, you are saying VM is utilizing 16GEG of mem (task manager?)?

4. What type of disks you are using for this VM? (vmdks or rdms)?

5. What are the other apps installed in this box (antivirus, tracerts etc)?

6. What time you generally run backups for this VM? Are snapshots committed at regular intervals?

Provide a screenshot of active CPU usage and virtual memory usage from performance and reporting window....

Thanks,,

Ramesh. Geddam,

VCP 3&4, MCTS(Hyper-V).

Please award points, if helpful

[wardb0071]

1. All the roles are on this box. We only have one Exchange Server (Only 35 mialbooxes) Not Heavily used.

2. Standalone VM

3. Looks like store .exe is killing it (see attached) The server used to have 8 GIG but it was always using 8 GIG, So I increased it to 16 GIG and now its always using 16 gig. Something corrupt with my store.exe?

4. Using an HP 4 GIG fiber SAN with 36x15k RPM drives

5. Antivurus is the only thing stored on here (+ Exchange 2007 OWA)

6. Exchange backups at around 10pm finishes by 11pm

I also run vReplicator that replicates the vm to the DR site, a snapshot is done every hour on the VM. (I do this with 10 other vm's and performance on those vm's are fine.)

Cheers,

[geddam]

This more looks an Exchange issue... I believe this issue is answered in technet..

http://social.technet.microsoft.com/forums/en-US/exchangesvradmin/thread/5a5a99e0-4eba-4b92-9167-3f60c7653a42/

Thanks,,

Ramesh. Geddam,

VCP 3&4, MCTS(Hyper-V).

Please award points, if helpful

[mlubinski]

It is the same for Exchange/SQL servers. These will always "touch" host memory (although showing guest mem usage 10% or so). Can't change it. Just observe guest mem usage, and if it does not hit 16gb, then lower ammount of assigned memory. I have exactly the same, but already got used to it :smileyhappy:

So first, check how much guest mem it shows on standard base, and if usage is ~50%, then lower RAM to this Exchange to 10GB and forget about it :smileyhappy:

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[wardb0071]

After observing my Guest Exchange VM, I see it using 14 of 16 GIG. 13 GIG of it for the Store.exe.

I ran an exchange trouble shooter and it said I have disk and memory page bottle necs.

Also said I have too many RPC Conections and RPC response times are slow.

I can't see why I would have these bottle necks with only 35 users and a 50 GIG database (25GIG Public and 25GIG Private)

I've opened a support case with microsoft to shed some light on the situation.

Thanks for all your help!

[mlubinski]

If you get response from MS, give us an info, can be useful for future troubleshooting.

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[PaulSvirin]

Here are the nice words from someone's blog:

"

A host system has a finite amount of memory that can be allocated to

guest virtual machines (VMs). Within the guest, the OS allocates and

de-allocates memory, constantly changing the amount of memory it's

actually using. The hypervisor only sees the allocation of memory from

the guest when the guest tries to read or write to a page of memory for

the first time. The hypervisor is never told when a page of memory is

de-allocated and put on the guest OS's free list. It's not practical for

a hypervisor to monitor each OS's implementation of the free memory

list because it would likely change between each OS version and service

pack. Therefore, the hypervisor only sees the memory use of each guest

grow over time, even though the guest may have stopped using large

amounts of the memory assigned to it.

"

Does it describe your situation?

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