Symantec GHOST IMAGING FOUNDATION 7.1, Manual, Page: 34 / 189

The image files created with Symantec Ghost have a .gho or .ghs extension by
default. They contain the entire disk or partitions of the disk. Image files support
the following:
■
Various levels of compression
■
CRC32 data integrity checking
■
Splitting of media files
■
Spanning across volumes
Symantec Ghost images contain only the actual data on a disk. If you have a 9 GB
drive with only 600 MB of data, the Symantec Ghost image is approximately 600
MB, or is smaller if you use compression.
You can use Ghost Explorer to selectively recover individual files from an image
file without restoring the complete disk or partition. You can also use Ghost
Explorer to edit Ghost images.
Image files and compression
Image files created in Symantec Ghost support several levels of data compression.
When Symantec Ghost is in interactive mode, three compression options are
available: none, fast, and high. The Symantec Ghost command-line switch -z
provides access to nine levels of compression.
See “About Symantec Ghost switches” on page 131.
As a rule, the more compression you use, the slower Symantec Ghost operates.
However, compression can improve speed when there is a data transfer bottleneck.
There is a big difference in speed between high compression and no compression
when creating an image file on a local disk. Over a network connection, fast
compression is often as fast as, or faster than, no compression. Over a parallel
cable, high compression is often faster than no compression because fewer bytes
are sent over the cable. Decompression of high-compressed images is much faster
than the original compression. The level of compression that you select depends
on your individual requirements.
The compression option is not available when you take an image of a drive that
uses BitLocker Drive Encryption.
Performance on a network
One advantage of Symantec Ghost is speed. It takes minutes to install an operating
system such as Windows XP, onto 10 or 100 computers. Many factors affect
performance.
Symantec Ghost support for image files and disks
Image files and compression
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