Personal website of Dave Hope » Virtual Server

Create Virtual Machine fails with error 3101

Dave — Fri, 09 Jan 2009 12:46:58 +0000

Over Christmas I completed migrating our SCVMM 07 environmentover to SCVMM 08. An issue appeared this week which had me stumped, all of a sudden creating VMs from some templates started to fail when trying to “Install VM Components”.

Error (3101) VMM failed to mount VHD file D:\BOH-DHOPE-V07\BOH-DHOPE-V07_disk_1.vhd on the * server. A timeout occurred. (Internal error code: 0x80990C1D) Recommended Action Check Device Manager/System Devices to make sure that Microsoft Virtual Server Storage Bus is installed and functional. If it is not, install VHDMount component of Virtual Server. Restart Virtual Disk Service, and then try the operation again.

This had started occurring on all our hosts where Virtual Server 2005 had been upgraded as part of the SCVMM 08 migration. Servers which didn’t need the Virtual Server 2005 update didn’t have this problem.

Setting VHD_MOUNT_TRACE=2 and trying to mount the VHD led to the following error:
The specified operation could not be completed as an unexpected error has occurred.

The workaround is to stop the Virtual Server service, uninstall Virtual Server and install again (from the ‘vs’ folder from SCVMM 08).

SCVMM 2008 Delayed

Dave — Thu, 09 Oct 2008 11:58:33 +0000

Microsoft were due to release SCVMM 2008 yesterday (8th October) but according to a forum post by Carmen Asher (a Program Manager at Microsoft) the release has been delayed until October 30th.

Ohh well, I guess that pushes our upgrade to SCVMM 2008 back a month – Darn.

Detecting VMWare

Dave — Wed, 06 Feb 2008 18:03:35 +0000

Interested in how to detect the presence of VMware / VirtualServer I came across this bit of code to detect whether an application is being run in virtual environment.
int swallow_redpill (){ unsigned char m[2+4], rpill[] = "\x0f\x01\x0d\x00\x00\x00\x00\xc3"; *((unsigned*)&rpill[3]) = (unsigned)m; ((void(*)())&rpill)(); return (m[5]>0xd0) ? 1 : 0; }
This works by abusing the SIDT instruction which stores the contents of the Interrupt Descriptor Table Register (IDTR) . It can be executed in ring3 revealing a sensitive register used by the OS. Because there can only be one IDTR the VM software needs to relocate the guest VM IDTR to a new point, which is software predictable.

Kudos to Invisible Things for an interesting read. There are some expansions on this code over at TrapKit for anyone who’s interested.

Windows 2003 Datacenter Guest NIC Driver for Virtual Server

Dave — Thu, 27 Sep 2007 08:44:20 +0000

Came across a problem the other day with running Windows 2003 Datacenter Edition as a guest on Microsoft Virtual Server. The problem? Windows 2003 Datacenter edition doesn’t have a suitable driver for Virtual Server, meaning that it’s fairly usless as a guest operating system (which negates one of the main benefits of having datacenter edition – unlimited VMs with no additional license cost).

I spoke to Peter Meister at Microsoft who was a great help, and whilst waiting for a solution from them I found some drivers which work. Install these drivers in your datacenter edition guest and your virtual network card will start working again, yay!