Take the 2-minute tour ×
Server Fault is a question and answer site for professional system and network administrators. It's 100% free, no registration required.

I've created a WIM file with filesize of 120MB (based on WinPE3.1).

When I add it to the Boot Images section, the presented filesize somehow became 746MB.

When I sniff the bandwidth of the network adapter while grabbing the image, I see that tha actual traffic passing is 386MB.

What is the correct filesize? Why are they so different?

share|improve this question

2 Answers 2

up vote 1 down vote accepted

Aceth is on the right path. The presented file size is the uncompressed size that the image will be once deployed. They are stored in compressed form, according to the TechNet article ‘Windows Deployment Services: Frequently Asked Questions’. Under the heading ‘What happened to the Single Instance Store’ it explains how WDS uses two files for each .wim image. Here is the relevant passage:

A Res.rwm file that contains all the file resources for all images in the image group. The data within Res.rwm is single-instanced and compressed; therefore, the Single Instance Store service is no longer needed. In fact, with Windows Deployment Services, the storage size on disk for images within an image group is greatly reduced, and it is more efficient than the storage mechanism used in RIS.

Additionally, at about the 36 minute mark in the TechNet Video ‘Deployment Day Session 3: Deployment Using WDS’, the host Rhonda explains how single-instance works.

Hope this helps

share|improve this answer

I've also wondered the same thing.

I believe it's all the compressed files. e.g. 120MB is the size on disk. 746MB is the images uncompressed size. The 386 is likely to be only needing to send what is required (e.g. drivers potentially)?

share|improve this answer

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.