We have two ways to update a pvs vDisk. Lets see both of them below:

Process 1 (official):

• Right click on a Standard Mode vDisk and choose version and create new version. This will create avhdx and pvp files. You can do this when there are existing connections on the vDisk.
• Set the update target device to maintenance mode.
• Boot the target device VM in hypervisor. While booting, it will prompt whether you want to boot into maintenance mode or regualr mode. Choose 1 and boot into maintenance mode.
• Install windows updates, software updates and power off the updater target device.
• Goto vDisk, versions, and promote the vDisk to test and boot the target device in test mode (Doesnt matter if there are connections on vdisk). Check if everything works as expected.
• Now promote the disk again to production. Till before step, earlier version will have green tick. Now you will see a green tick to the promoted version.
• Now you have to merge this new version to base version. If you have multiple versions (i.e., avhdx file for each version) which are not merged with base, you can merge/consolidate all those updates into one avhdx. Use “Merged updates” option to do so. As the name says, you can merge/mix updates (avhdx files) into one avhdx file.
• If you have avhdx (use merged updates if you have multiple avhdx files) file and want to merge it to the base disk, use “Merged Base” option. This will merge avhdx and vhdx versions and create one vhdx file. All your changes you did in avhdx are merged to the base disk and users will see the new changes after they restart their VDIs.
• Again in this step you can set it to maintenance or production or test versions.

After merge base is done, you will see 3 versions overall. On a new or very first vDisk update, 0 will be the base version and version 1 for merging avhdx with vhdx, and version 2 is the final merged base. You will see a red X button next to the version 1 in the console because when you created a new version, it will create it as version 1. When you merge, version 2 would be created. version 0 is the base and version 2 is the new updated vDisk. Version 1 doesn’t have vDisk file (check in your store folder, you can’t see vhdx file for version 2). You can delete this version if you want.

Process 2:

This is very simple and straight forward process.

• Copy your existing vDisk file and rename it some like vDisk2.vhdx.
• Add it to pvs console. Make sure you don’t have any special characters in the filename. Ex, vDisk1.1.vhdx etc. Rename as vDiskName2.vhdx.
• Attach this vDisk to updater target device. Leave updater target device in production mode and boot from vDisk.
• Login to this updater target device and install updates like windows udpates, application updates etc.
• Shutdown the updater target device. Make sure this updater target device lock is removed from the vDisk. Attach this vDisk to one or two production target devices and test.
• If everything works as expected, drag this new vDisk from vDisk store to required device collection. Upon reboot all the target devices in that device collection will get this new vDisk.
• Retain old vDisk for backup purpose. Once you update vDisks with this process you will end up in multiple vhdx files in your store. Maintain minimum one or two backup vDisks and delete rest of other old vDisks.