Space Requirements for ZEN Imaging
Novell Cool Solutions: Feature
By Drake Backman
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Posted: 24 Jan 2001
Current version: ZENworks for Desktops 3
Drake Backman is the lead engineer for ZENworks Imaging, and in fact was the guy who designed and wrote the Imaging engine (the Linux app).
We've had some anxious inquiries from customers who fear they'll need gargantuan amounts of storage space if they want to use ZfD3 Imaging. Typically they have something like 15-20 different images they need to create, each from a 12 GB hard drive. Question: Since ZEN Imaging currently does not provide any image compression, do they need 240 GB to store the needed images?
The answer is no, assuming the hard drives are formatted for either FAT or NTFS. The size of the image files is determined not by the size of the hard drive or even of the partitions, but by the amount of data stored on the drive. A fresh installation of Windows 2000 Professional usually results in an image size of about 650 MB, regardless of the size of the partition or hard drive. If all images are Windows 2000 Professional images, then the total amount of storage is closer to 13 GB than 240 GB.
Furthermore, it is usually possible to reduce the needed space even further by using the add-on imaging technology that is unique to ZENworks. Assuming your hardware is relatively similar, and the only difference in your various images is which applications are installed, then we have good news for you. Create a single base image of your OS with ZENworks (specifically NAL) installed. Then create add-on images for each of your applications using NAL. You can now use these images to mix and match to create the final images you need.
Consider the following example. At company XYZ, the receptionists need Windows ME with MS Office 98 and Internet Explorer. The writers need Windows ME, MS Office 98 and Adobe Acrobat. The support people Windows ME, Outlook Express and an in-house application. The facilities people need Windows ME and Internet Explorer. In traditional imaging solutions, each of these roles requires its own image that needs to be created and maintained separately. When an update to Windows ME is published, all four images must be updated. There is also a great deal of redundancy in each image, since the majority of the files in each image are OS files.
With ZENworks Imaging, you could make a single base image of Windows ME, and the add-on images of MS Office 98, Internet Explorer, Adobe Acrobat, and the in-house application. The resulting images are much smaller, and easier to maintain and ZENworks allows you to mix and match these images to get the final image you want. I call the final image the aggregate image, since it is an aggregation of the two or more smaller images.
Granted, this scenario is ideal, since all stations take the same OS and can use the same base image, but it is not far from most companies' reality. You may need to have several base images and base images for several different OSs, but the add-on images can be created once and placed on any base image. You still reduce the disk space needed and the amount of maintenance needed when any application or OS is updated or patched by the manufacturer.
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