Investigating busy hosted virtual machine files

Products

• VMware
• VMware Desktop Hypervisor

Issue/Introduction

This article guides you through determining if problems being experienced by a virtual machine are related to other software on your host trying to access virtual machine files. The article also offers means of correcting this situation.

Symptoms:

• Unable to open file.
• Insufficient permissions.
• Virtual machine runs slowly.
• Virtual machine becomes unresponsive.
• Virtual machine crashes.
• Virtual machine file corruption.
• Guest operating system data corruption.
• Cannot power on virtual machine.
• Unable to successfully perform snapshot operations.
• Unexpected behaviour in guest operating system.

Resolution

To ensure optimum performance and data integrity, VMware requires exclusive disk access to all of the files that comprise the resources of a virtual machine while it is powered on. If another program accesses one of these files at the wrong moment, unexpected results may occur.

For information on determining the location of virtual machine files, see Locating a hosted virtual machine's files (1003880) .

The following are the types of software and activities that may interfere with normal virtual machine operation, and the steps to take in order to ensure that they do not cause a conflict:

• Antivirus software. Exclude all of the virtual machine files from manual, automatic, and real time scanning. Limit antivirus scanning of virtual machines to the guest operating system inside the virtual machine. If an antivirus scan of the virtual machine files is required ensure that the virtual machine is powered off prior to the scan.
  
  
• Backup software. Exclude all virtual machine files from host file backups. If a virtual machine needs to be backed up it can be done from the guest operating system inside the virtual machine. If the virtual machine files themselves need to be backed up ensure that the virtual machine is powered off prior to the backup.
  
  
• Disk utility software. Do not run host disk integrity checks, defragmentation routines, or anything else that involves writing to the disk or otherwise accessing files, on any of the virtual machine's files while the virtual machine is powered on.
  
  
• Other software. This includes spyware, P2P applications, and anything else that may be accessing one of the virtual machine's files. Operations that make use of the files include reading, scanning, copying, and writing. Exclude the virtual machine's files from any of these operations.
  
  
• Editing of virtual machine files. Do not edit any of the virtual machine's files while it is powered on.