We are using Arcserve 6.61 and a DLT 7000 tape drive (hardware compression enabled)for one of our backup solutions. Once this backup job hits about 80GB of data the job spans to a second tape and finishes off around 100GB. When reviewing the arcserve log it show that the media compression ratio for the job was 2.37. I am a bit confused because if this were really the case then roughly 43GB of compressed data would be written to tape throughout the course of the job, since a DLT 7000 can write 70GB of compressed data to tape then the job should not need to span to a second tape? Right? I am trying to figure out exactly what arccserve it telling me when it says "media compression ratio 2.37"? Any insight would be greatly appreciated!
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Media Compression Ratio
- Thread starter waricka
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The 70 in a DLT 35/70 represents how much data can be put on tape based off 2:1 compression. This however, is often not the case in real life - as the amount of data compression is highly dependant on data type. Try to backup a disk full of .zip files, you'll get no compression. Backup a disk full of .txt files, you'll get 100:1 compression.
In this case ARCserve is stating you are getting 2.37:1 compression. Based off native capacity of 35 gigs - that means you should be getting roughly 83 gigs on each tape.
In this case ARCserve is stating you are getting 2.37:1 compression. Based off native capacity of 35 gigs - that means you should be getting roughly 83 gigs on each tape.
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