You can configure Flash Read Cache for your virtual machine.

Before you begin

Set up virtual flash resource.

About this task

Enabling Flash Read Cache lets you specify block size and cache size reservation.

Block size is the minimum number of contiguous bytes that can be stored in the cache. This block size can be larger than the nominal disk block size of 512 bytes, between 4 KB and 1024 KB. If a guest operating system writes a single 512 byte disk block, the surrounding cache block size bytes will be cached. Do not confuse cache block size with disk block size.

Reservation is a reservation size for cache blocks. There is a minimum number of 256 cache blocks. If the cache block size is 1 MB, then the minimum cache size is 256 MB. If the cache block size is 4 K, then the minimum cache size is 1 MB.

For more information about sizing guidelines, search for the Performance of vSphere Flash Read Cache in VMware vSphere white paper on the VMware web site.

Procedure

  1. Navigate to the virtual machine.
  2. Right-click the virtual machine and select Edit Settings.
  3. On the Virtual Hardware tab, expand Hard disk to view the disk options.
  4. To enable Flash Read Cache for the virtual machine, enter a value in the Virtual Flash Read Cache text box.
  5. Click Advanced to specify the following parameters.

    Option

    Description

    Reservation

    Select a cache size reservation.

    Block Size

    Select a block size.

  6. Click OK.