Provisioning Services works differently than Machine Creation Services to provide resources to the users. PVS allows machines to be provisioned and re-provisioned in real time from a single shared vDisk. So the administrators can manage and update only on the master vDisk, in some case we can remove from the system itself.
The MCS provisioning machine is all about storage and PVS relies on network. Simple process with PVS is, start off with Master Target Device, capture the disk as a new vDisk and then provision the vDisk to the target devices. The AD-identity (SID) comes from an additional disk in MCS and PVS uses SQL database for this.
After installing and configuring PVS, vDisk can be created by imaging a hard disk (contains OS with Applications) and this vDisk file is stored on the network. The device which is used to create the vDisk is called Master Target Device and the devices that use the vDisk are called target devices.
Updates and writes with MCS are saved to a Differencing Disk, while writes with PVS are saved to a Write Cache.
The target devices download a boot file from the PVS and then use that boot file to start. Based on the device boot configuration settings the appropriate vDisk is located and then mounted on the PVS server. The application and the desktop OS on the vDisk are streamed by the PVS server to the target device.
Instead of pulling down all of the vDisk contents to the target device, the date is brought across the network in real time which dramatically reduces the amount of network bandwidth thereby supporting a larger number of target devices on the network without impacting overall network performing.
Difference between MCS and PVS
PVS working process
- A target device powers on and uses TFTP to download bootstrap file (ARDBP32.BIN) which provides the target device with the connection required to get its vDisk.
- TD uses Bootstrap file to request that PVS to send the boot sector from the vDisk.
- PVS access the vDisk from the Store (storage) and dynamically merges the boot sector with the SQL server data to apply appropriate SID based on the MAC address of the TD.
As the target device starts up, further requests for additional sectors from the vDisk are access in the same method. With PVS the entire vDisk is not streamed instead sectors are sent to the target device as needed.