Compression question

The technical support forum for Firestreamer (the virtual tape library).
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virtualme
Posts: 1
Joined: 13 Dec 2010, 18:42

Post by virtualme »

If the drives where Firestreamer is storing virtual tapes is compressed, does this impact the amount of compression Firestreamer can achieve? Also, is there a compression ratio that is the average achieved by Firestreamer when used by MS DPM 2010?
jsf
Cristalink Support
Posts: 300
Joined: 29 Aug 2010, 09:03

Post by jsf »

If you were using the Firestreamer compression with file media on compressed drives, it would negatively affect the performance without increasing the compression ratio. In other words, the only result would be the higher CPU usage caused by the file system unsuccessfully trying to compress already compressed data. Generally, compressed data is not compressible any further, regardless of the original compression ratio.

You should use either the Firestreamer compression or the file system compression, but not both. The compression ratio depends not on the backup software but on the data itself. If you were backing up files consisting of binary zeros only, the compression ratio would be several hundreds. For video and image files, the compression ratio would be 1 (no compression).

Please see What is the data compression ratio of Firestreamer for more details.
Best regards,
John Smith
Cristalink Support
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