Tape capacity difference

[Amaan]

Hi, I have a question. My question is from attached screenshot:

All tapes are same tapes and we have only one tape drive but they are becoming full in different size. One is 522778560, another one is 863286528 and third one is even more 1567017472. Why they are becoming full in different points?

Sorry if this question is ever been answered before.

Thanks!

[Marianne · Accepted solution]

Different types of data compress differently - some good, giving your more data written on tapes. Some data does not compress well or allow no compression at all, giving you less data on tape.

Always use uncompressed capacity for planning purposes. Anything above that is a bonus!

[Amaan]

We are not doing any compression while doing a backup.

[J_H_Is_gone]

most people have hardware compression on the tape drives by default.

[Amaan]

How i can find if it is exists? How do i know if the compression is enabled in the drive.

and i told that we are not doing compression from NB end.

[Will_Restore]

The LTO specification describes a Data Compression method LTO-DC, also called Streaming Lossless Data Compression (SLDC).

^{http://en.wikipedia.org/wiki/Linear_Tape-Open#Compression}

[Amaan]

Thanks so much for all. My question has been answered and i am marking Mariannes answer as a solution.