Defragmentation in VMWare

This post was most recently updated on December 11th, 2018

Host Hard Drives

Performance is weakened by fragmentation on the physical disk holding the virtual machine’s working directory or virtual disk files. Fragmentation of the host disk can affect any or all of the following:

• The files that hold a virtual disk
• The files that store newly saved data when you have a snapshot
• The files that hold information used in suspending and resuming a virtual machine

If you are experiencing slow disk performance in the virtual machine, or if you want to improve the speed of suspend and resume operations, check to be sure the host disk that holds the virtual machine’s working directory and virtual disk files is not badly fragmented. If it is fragmented, you can improve performance by running a defragmentation utility to reduce fragmentation on that host disk.

Bron: http://www.vmware.com/pdf/ws55_manual.pdf pagina 434

You may see slower virtual machine performance if the physical disk that holds the virtual machine’s working directory or the physical disk that holds the virtual disk files is badly fragmented. By default, the working directory holds the virtual disk files and is on the host computer. If you have customized the virtual machine configuration, you may have placed the working directory or the virtual disk files on a different physical computer.

Fragmentation of the host disk can affect any or all of the following:

•  

  The files that hold a virtual disk

• The files that store newly saved data when you take a snapshot
•  

  The files that hold information used in suspending and resuming a virtual machine

If you are experiencing slow disk performance in the virtual machine, or if you want to improve the speed of suspend and resume operations, check to be sure the host disk that holds the virtual machine’s working directory and virtual disk files is not badly fragmented. If it is fragmented, you can improve performance by running a defragmentation utility to reduce fragmentation on that host disk.

Defragmenting Virtual Disks

Like physical disk drives, virtual disks can become fragmented. Defragmenting disks rearranges files, programs, and unused space on the virtual disk so that programs run faster and files open more quickly. Defragmenting does not reclaim unused space on a virtual disk; to reclaim unused space, shrink the disk.

For best disk performance, follow these steps:

1. Run a disk defragmentation utility inside the virtual machine.
2. Power off the virtual machine, then defragment its virtual disks from the virtual machine settings editor (VM > Settings). Select the virtual disk you want to defragment, then click Defragment.

   • Note: This capability works only with virtual disks, not physical or plain disks.
3. Run a disk defragmentation utility on the host computer

Defragmenting disks may take considerable time.

Note: The defragmentation process requires free working space on the host computer’s disk. If your virtual disk is contained in a single file, for example, you need free space equal to the size of the virtual disk file. Other virtual disk configurations require less free space.

Bron: http://www.vmware.com/pdf/ws55_manual.pdf pagina 207