When the Windows OS goes into hibernation mode, a significant amount of write storage I/O is required to write the contents of the system's RAM to the hiberfil.sys file. An equivalent amount of storage-read I/O is needed to resume the desktop from hibernation. During periods of heavy use, this additional I/O may affect the performance of other desktops that share the same storage. In addition to that, the hiberfile.sys file requires disk space equivalent to that of the desktops, configured RAM, which further increases the amount of per-desktop space required. To reduce desktop storage utilization, hibernation should be disabled.
To disable hibernation, execute the following command from an elevated Windows Command Prompt:
powercfg /hibernate off
If required, Horizon can manage workstation power states using native vSphere features. Desktops can be powered down or suspended as required, based on the configuration of the desktop pool. These settings are discussed further in Chapter 7, Creating Horizon Desktop Pools.