size on media after copy1 on msdp

[guilhemlflo]

Hello, I have a copy1 backup on msdp with a compression ratio of 98%.

Then I have a copy 2 on LTO6 tape.
My question is: when sending data to tape, what size is set to tape?
Real size or compressed size?
This would allow me to know how much tape per week / month I need to predict.

Thanks

[VirgilDobos · Accepted solution]

Hi there,

When duplicating data from MSDP to tape, the backup images need to be rehydrated, hence the size on the tape would be the same as the original data that you are backing up, if no compression is used. If tape compression is enabled, the amount of storage used would depend on the data type and the level of compression that you are using.

[Nicolai]

When copying data from MSDP to tape, data from MSDP will be re-hydrated to its full size and send to the tape drive, but the LTO tape drive will apply compression internally to the incoming data. The compression rate on tape is dependant on data type (e.g. database = good, encrypted data = bad).

Hint: take a average on tapes native capacity vs. actual stored data on all the tapes you have. The media manager tab will show tapes and how much data are stored on them.

Best Regards

Nicolai

[guilhemlflo]

thanks you for the answers.