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Citrix Provisioning Services (Citrix PVS) is a software-streaming technology that delivers patches, updates, and other configuration information to multiple virtual desktop endpoints through a shared desktop image.
The goal of Citrix Provisioning Services is to centralize virtual machine management and reduce the operational and storage costs of a desktop virtualization environment.
Citrix PVS configures servers in the data center, which Citrix refers to as Provisioning Servers, for use with the company's desktop virtualization products XenApp and XenDesktop. All virtual desktops on Provisioning Servers are built from one golden image, so administrators only need to apply policy changes or operating system and application patches to one disk image for an entire farm of servers.
PVS streams updates to the individual servers in real time when they reboot. Normally, when using a single shared disk image, latency and boot performance can slow the delivery process, but PVS caches a copy of the updated disk image on the server's RAM and boots virtual desktops from the server RAM instead of the original disk. Admins can also use PVS to roll back to previous versions of the master image.
Citrix recommends making shared disk images read-only for security purposes, but PVS configures a unique write cache for each virtual desktop instance, which allows users to interact with their virtual desktop interface normally.