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vmjoe
Enthusiast
Enthusiast

Strange problem: VM won't start with more than 4032 MB RAM assigned

Hello

I encountered a very strange problem with a Windows 2003 VM and have no idea how to solve it.

The problem started when the VM was cold migrated from an old host to a new one, got a VMware Tools update and the requested reboot. Then the VM did not start anymore, resetting after less than a second (even before showing any Windows splash screen).

Even Safe Boot, Last Known Good etc. didn't really help; it would maybe start till the logon screen in safe mode but resetted (without blue-screen) a few seconds later.

I tried a lot of things: attaching to 2nd VM for chkdsk, disabling VMware Tools service by editing the registry hive, recovery console, new vm with just disk attached, etc. pp.

No joy. Then I configured the VM with just 1 CPU and 1 GB RAM, and it started! Tried 2nd CPU, 4 CPUs, more RAM - bang, problem back. I iteratively narrowed it down to this, 100% reproducible:

4032 MB RAM works

4036 MB RAM doesn't work 😮

To make it even sweeter, if I hot-add RAM (beyond 4032 MB) after the VM started, it works! To make it even more interesting, I can reboot the VM then and it still works! But if I shutdown the VM and restart the VM container with more than the magic 4032 MB, it resets immediately! 😮

I have another "identical" VM on that cluster, and there's no problem at all.

Any hints where to look?

More information:

- vHW9

- 4 vCPU, 8 GB vRAM (initially)

- The VM was originally (long time ago) created by P2V I guess (it has a virtual USB controller device)

- W2K3 Enterprise 32 bit SP2

- Memory Hot Add enabled

- ESXi 5.1.0 build 1483097

- Critial system files are identical to a working system (hal.dll, ntdetect.com, ntldr, ntoskrnl.exe, boot.ini)

- chkdsk, fixmbr, fixboot done

- VMware Tools reinstalled

- Booted on different hosts (even on the "old" cluster)

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3 Replies
schepp
Leadership
Leadership

Hi,

sounds strange indeed. By the way, when this VM is running w2k3 32bit, it can't use more than ~4GB RAM anyway.

Regards

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a_p_
Leadership
Leadership

Only a guess. Can you confirm that "Windows Server 2003 Enterprise Edition" is configured in the VM's settings?

André

Note: A 32-bit Windows Server 2003 Enterprise Edition uses 36 bits with /PAE enabled, and can therefore theoretically manage up to 64GB RAM.

vmjoe
Enthusiast
Enthusiast

The VM is configured as "Microsoft Windows Server 2003 (32-bit)". There's no "Enterprise Edition" explicitly listed anymore in ESXi 5.1 as in previous versions.

In the vmx file this leads to the entry guestOS = "winnetenterprise" however.

We found that if we disable "Memory Hot Add" for this VM, then a startup with 8 GB RAM is possible.

All other VMs (including a very similar P2Ved VM) do not have a problem with "Memory Hot Add" enabled - strange.

Also, as described before, if "Memory Hot Add" is enabled but the initial amount of RAM is not higher than 4032 MB, hot adding also works for this VM! :smileyshocked: