Backup Exec not use total capacity of tape

[Cagy]

We use the BE 12.5 with a Tandberg Ultrium 3, over the weekend to start hardware error instructing you to replace the tapes used and make cleanup.

Made it up ran "smoothly" until the end it asked a third tape.

I was using 2 LTO3 tapes to back up about 460 Gb

Like this:



tape 1

Used Capacity: 389.9 GB of 390.9 GB

Data: 221.19 GB

Compression Ratio: 1:1



tape 2

Used Capacity: 389.9 GB of 390.9 GB

Data: 237.01 GB

Compression Ratio: 1:1



From what I understand, he did not use the full capacity of the tapes and also asked a third.

I ask for help from the community.

Thank you.

[CraigV]

Hi,

What type of data are you backing up? Compressed data does have the tendency to rehydrate meaning you don't fit as much data onto a tape, and then leaves your job spanning additional tapes. It might explain your 1:1 compression, but check and make sure that compression is enabled on your backup job.

Also, faulty tapes can result in compression rates dropping. Check for Hard Write Errors under the Devices tab of your media server. You can try erasing a tape using your drive manufacturer's diagnostic utility and then trying again.

Thanks!

[Ken_Putnam]

Are you trying to use software or hardware compression?

From the devices tab, right click the drive\properties and verify that "enable compression" is selected

Some tape devices have a switch on them to enable or disable hardware compression.  If you are trying to use hardware compression, verify that this is in the "enable" position  (see the users guide for the tape device)

[Cagy]

compression is enabled by hardware if possible.

the tapes are new, have used two new sets of tapes.

[Cagy]

in Job, compression is enabled by hardware if possible.

in the devices tab, right click the drive\properties, "enable compression" is selected

[Ken_Putnam]

OK, that looks good

Try stopping all BackupExec services and running a pass or two of the manufacturer's diagnostics agains the drive

(When using hardware compression, even when it works, BackupExec will show a 1:1 ration if it shows anything at all, since it sends uncompressed data to the drive itself, and has no way of knowing what ratio the drive will attain, if any )

[pkh]

Are you using encryption?  If you are, you should be using both software encryption and compression.  You should not be using software encryption and hardware compression because encrypted data do not compress well.

There is another user who reported that his drive was not compressing data because it is faulty.

Other than hardware problems like faulty tape &/or tape drive, as suggested earlier, check your data for compressed data, like zipped files and movies, sound and picture files.  These does not compress well.  See my article on this subject.

https://www-secure.symantec.com/connect/articles/compression-short-explanation

[Cagy]

The type of bases are basically nsf files of Lotus Notes. Always worked.

[pkh]

When hardware compression is working, you will always see a compression ratio greater than 1.  See below

[pkh]

Try using software compression and see what compression ratio do you get.

[Cagy · Accepted solution]

after running the head cleaning utility for recording unit, apparently resolved.

Tks all.