Compact Profiles
Significantly reduce the size of the VHDx images by removing unused installation files, compressing or defragging the vDisks, expect up to a 50% of size reduction. Only bases will be compacted but not differencing vDisks.
Apply Compact Profiles to vDisk Groups. To take advantage of the Compact Profile, the Windows volume where the operating system is running must be the last volume on the disk.
In default formatted systems, Windows may have created a recovery partition as the last partition in a disk. This partition is not necessary in Host Provisioning and will prevent the compact process to reduce the size of the vDisk. Safely remove the recovery partition and upload the VHDx again if necessary, you may need to use DISKPART selecting the disk and the recovery partition number, delete it with the override option.
For example, remove the recovery partition from disk 0, make sure to select the right partition:
DISKPART.exe
DISKPART> SELECT DISK 0
DISKPART> LIST PARTITION
DISKPART> SELECT PARTITION 3
DISKPART> DELETE PARTITION OVERRIDE
Available options for a Compact Profile.
| Option | Description |
|---|---|
| Profile Name | The name that identifies the profile |
| Remove Updates | Rebase and remove updates from image, you won't be able to roll back an update after rebasing. Depending on the number of updates this can save 1-2 GB |
| Remove Features | Removes not installed features from the image, if you need to install a feature after being removed, it'll be downloaded from the internet. Beginning with Windows 10, the payload is not removed from Windows client editions in order to support Push-button reset, this option will have no effect on Client editions and it'll be ignored. The payload is removed from Windows Server installations |
| Compress Files | Compress files on the image using the selected algorithm. This will greatly reduce the size of the image up to 50%. This is a trade-off between CPU usage and I/O disk access resulting in an overhead of CPU and less disk access. The actual performance impacts really depend on the relative performance of the storage device and the compute device. Compression means fewer reads, which removes load from the storage device and improves I/O performance; and more decompression, which adds CPU load and decreases performance, depending on your system configuration it can improve the system's speed, normally it has few effect on performance |
| Compress Algorithm | Compress algorithm used by wof.sys driver. - LZX for strongest compression. - XPRESS16K - XPRESS8K - XPRESS4K for lightest compression |
| Defrag | Moves all the clusters to the beginning of the vDisk, compacting the disk after defragging is very effective, this is highly recommended, even if you the image is not being compressed |
Make sure to backup your VHDx image before applying a compact profile.
Applying compact profiles to a vDisk after being uploaded is an intensive CPU and I/O process that may take some time. We highly recommend setting antivirus exclusions to the processes or files involved.
Host Provisioning uses the WOF (Windows Overlay Filter) compression to create an alternate data stream. Decompression on-the-fly of WOF compressed files is handled transparently by the wof.sys driver. Make sure to install the Host Provisioning Client in the VHDx image, otherwise the server might be unable to initialize the WOF driver. Compression is compatible with BIOS, UEFI and UEFI with Secure Boot enabled.
When a host is in MANT mode and a compact profile is selected for the computer, it performs a compact os operation, allow it to finish before uploading the vDisk to the server.