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DaleMahalko
Guest
I am trying to determine what the particular uses are for having multiple Image Groups on Windows Deployment Services.
So far my web searches are not turning up anything useful, and I can't find a WDS-specific forum so sorry if this is the wrong area to ask about this.
,
Single Image Group -- saves on disk space?
WDS creates a single "Resource.WIM" containing all images in the image group.
It appears that this is by design space efficient because files of the same exact size are not duplicated across the images, and the separate image resource file stores only the file path, version, modification date, security, etc, all of which is very small and easily contained in a few megabytes.
So the first Windows 7 image upload will take up gigabytes, but additional uploads will be much smaller because the core of the system files will duplicate what was in the first image.
It appears that eventually you can reach a point where additional uploads end up only needing a few megabytes to store the entire new image, because all the data for this upload already exists spread across all the data files previously uploaded to the Resource.wim
It also appears that you can be indiscriminate about what you upload to the Image Group. Want to upload XP and Vista and Windows 7 to the same group? That appears to be perfectly fine, and poses no file conflict problems.
This strategy may apparently potentially work to your favor because likely some system files in XP duplicate files from Vista, and also in Windows 7, so there's even more disk space savings by putting everything into a single Image Group, not to mention the duplication of application files across images.
,
Image Groups -- Intended for Access Control to images?
So why do you need additional Image Groups at all? It appears that for a basic WDS implementation, one Image Group is all you need, and creating more of them for "OS segregation" is simply a waste of disk space because the new group needs an all-new Resource.WIM of its own, which will no doubt duplicate much of what is in the other Resource.WIM's of your other Image Groups.
As far as I can tell the only reason to create additional image groups is to restrict access to images, so that for example a school computer lab technician can only access images intended for the lab computers, and is prevented from accessing images for the accounting and administrative offices.
But if you have no need to implement image access security or restrict access to various types of drive images, then implementing additional image groups is mostly pointless and will just waste server disk space.
,
Image groups .. and file corruption?
Another possibility for wanting more than one Image Group is that perhaps additional image groups can protect your images from file corruption such as from a bad image upload. Though I do not know if corruption of an Image Group is even possible.
Apparently if an image upload fails for some reason, the corrupt files will not overwrite anything else but would just be written out as additional files in the Resource.WIM .. and then possibly never accessed again and perhaps not be removable from the Resource.WIM since the image upload failed before completion.
If this is the case, then a failed upload apparently just means "Image Group bloat" because the Resource.WIM can never shrink and remove the uploaded image files, but probably no actual damage to previously uploaded images will occur?
,
Can anyone help to clarify these questions for me, or suggest a more appropriate forum?
- Dale Mahalko
Continue reading...
So far my web searches are not turning up anything useful, and I can't find a WDS-specific forum so sorry if this is the wrong area to ask about this.
,
Single Image Group -- saves on disk space?
WDS creates a single "Resource.WIM" containing all images in the image group.
It appears that this is by design space efficient because files of the same exact size are not duplicated across the images, and the separate image resource file stores only the file path, version, modification date, security, etc, all of which is very small and easily contained in a few megabytes.
So the first Windows 7 image upload will take up gigabytes, but additional uploads will be much smaller because the core of the system files will duplicate what was in the first image.
It appears that eventually you can reach a point where additional uploads end up only needing a few megabytes to store the entire new image, because all the data for this upload already exists spread across all the data files previously uploaded to the Resource.wim
It also appears that you can be indiscriminate about what you upload to the Image Group. Want to upload XP and Vista and Windows 7 to the same group? That appears to be perfectly fine, and poses no file conflict problems.
This strategy may apparently potentially work to your favor because likely some system files in XP duplicate files from Vista, and also in Windows 7, so there's even more disk space savings by putting everything into a single Image Group, not to mention the duplication of application files across images.
,
Image Groups -- Intended for Access Control to images?
So why do you need additional Image Groups at all? It appears that for a basic WDS implementation, one Image Group is all you need, and creating more of them for "OS segregation" is simply a waste of disk space because the new group needs an all-new Resource.WIM of its own, which will no doubt duplicate much of what is in the other Resource.WIM's of your other Image Groups.
As far as I can tell the only reason to create additional image groups is to restrict access to images, so that for example a school computer lab technician can only access images intended for the lab computers, and is prevented from accessing images for the accounting and administrative offices.
But if you have no need to implement image access security or restrict access to various types of drive images, then implementing additional image groups is mostly pointless and will just waste server disk space.
,
Image groups .. and file corruption?
Another possibility for wanting more than one Image Group is that perhaps additional image groups can protect your images from file corruption such as from a bad image upload. Though I do not know if corruption of an Image Group is even possible.
Apparently if an image upload fails for some reason, the corrupt files will not overwrite anything else but would just be written out as additional files in the Resource.WIM .. and then possibly never accessed again and perhaps not be removable from the Resource.WIM since the image upload failed before completion.
If this is the case, then a failed upload apparently just means "Image Group bloat" because the Resource.WIM can never shrink and remove the uploaded image files, but probably no actual damage to previously uploaded images will occur?
,
Can anyone help to clarify these questions for me, or suggest a more appropriate forum?
- Dale Mahalko
Continue reading...
