VMWARE guest stars slower when more ram added

[petersb]

Hi all,

I have a HP ML370 G4 Server with 8GB ram. The server itself is running windws 2k3 enterprise edition. We use this box for some simple testing. We have the host OS installed on 3 147gb Ultra320 10K drives in raid 5. We have another 3 of the same except they are 15K drives for guest storage

One of the guests is a 2k3 standard edition server running within VM server. This guest hosts a sql db for us. It has been running fine with 1GB of ram assigned however one of the users is doing some complex query testing and asked if we could assign more ram. I assigned an additional 1gb and when i do this, the server runs extremly slow. When I change it back to 1GB it is fine. I started it again with 2gb this time disabling all non-essential services especially sql with no difference. I have no other guest running on it. I have no idea why this is the case. Is this alimitation of running on a windows host?

Any help appreciated

 

[SimonDavies]

Hang on, this isn't making sense, you say that the server itself is running 2K3 Enterprise server... with that in mind can we assume you're running either VMware Server or Workstation rather than VI?

If you are assigning more RAM to guest OS's what impact does that have on the physical host? Does that slow down noticiably?

Unless you have something using all of the ram on the HOST I can't think of a simple reason why this may happen, generally speaking as long as the HOST isn't utilising the RAM then it should actually improve the GUEST when you add additional ram, the only thing I can think of at the moment is that the GUEST is using part physical ram and part virtual ram (ie the HOST is having to page).

Simon

The real world is not about exam scores, it's about ability.

 

[petersb]

Thanks Simon,

Yes it is VMware Server we are using and last night after writting the post I did the following:

Checked to make sure that i have VMware set to use only system memory, no swapping.

The Host does not show any evidence of slowing dows. CPU and memory avialability is acceptable

Yesterday i observerved the following boot timings:

With 1GB assigned the server took on average 3:26 to boot

With 2gb 5:43

The average was based on 5 boot cycles on each with clean shutdowns.

We are thinking of changing this test environment over to ESX. I have played with it before but know little. One thing I want to ask is, with ESX are the vm images as portable as they are with VMserver? When I had ESX running before it seemed like the only way i could get images off and on the server was using the vm converter tool. Sometimes we have images on the server which we want to take off and put on a laptop is it easy to access the esx files? can the esx files run on vm player?

Thanks again

Regards

 

[biglebowski]

Don't know if this applies for server as I've never used it but I've seen this issue using cloned templates.

Check if the resource allocation for your machine is still set to 1GB even after increasing the vm ram.



When I was born I was so suprised I didn't talk for 18 months

 

[SimonDavies]

At a guess you would want to be using VM Converter, the difference in supported hardware between different versions of VMware is quite large (for instance Workstation supports USB2 where as ESX doesn't even support USB natively).

Convertion doesn't take that long and at least it keeps your environment neat and tidy.

Simon

The real world is not about exam scores, it's about ability.

 

[nhidalgo]

was anything changed in the boot.ini on the host server? Possibly the /#3GB switch, as this should not be there and could cause a problem. Just a thought.

Also when you boot the vm if you watch task manager, do you see the 2GB of ram fully taken by vmware before vm completely boots? It could be the time it takes to build the vm's swap file.

I had a similar problem with vmware server 2.0, the old version of server didn't do this and esx and workstation also don't have this problem. As a test, download vmware workstation demo and boot your vm via that hypervisor on the same server with the same config

 

[petersb]

I have noticed some other strange behaviour perhaps someone can help me with. When I have 1024mb ram assigned to this guest the server is consuming just over 1gig on the host when the guest reaches the log on screen. However when I assign 2 gig to the same guest, by the time it gets to the log on screen it is only consuming 177MB on the host.