Backup Exec 2010 reports incorrect available capacity

[WaltSakir]

We are using LTO Ultrium 4 tapes which have a 800GB capacity.  In the Devices tab under the "Used Capacity" column it reports the total available capacity as 745.1GB.  These are all new tapes we are using.  Why is there a difference between the available capacity in Backup Exec and what the tape capacity is capable of using?

[pkh]

Total Capacity is how much data the tape can hold without compression.  When you format your LTO4 tape, you will get a figure less than 800GB.  This situation is like when you format a 500GB and you only get about 400GB+ of capacity.

The Total Available Capacity is the capacity left after you have written some data to the tape. 

[WaltSakir]

Yes I understand the idea of formatting a tape and getting less than the total capacity without compression but the total available capacity is about 45GB less than what the tape is capable of holding.  That seems excessive to me.

[WaltSakir]

In the last post I meant to say it is 55GB

[pkh]

Go to the Media tab, click on the tape that you are referring to and post a screenshot of the tape statistics in the lower pane.  I will try to explain the statistics.

[WaltSakir]

Attached is the screenshot you requested

[pkh]

You are right in that you are getting only 745Gb in total capacity.  I am getting 781Gb on my LTO4 tapes, but I am using HP tapes and drive.  Do you have an IBM utility to format the tapes?  Maybe you can try using it, rather than using BE to format the tapes.  Otherwise, you should check with IBM.

[WaltSakir]

I do not think it is the brand of tape because I tried another tape brand(TDK) and received the same results in total capacity.   When you said to format the tapes are you talking about using the quick erase feature? 

[Ken_Putnam]

doesn't directly answer your question, but if you run a backup to one of these tapes (with no compression)   that exceeds 800GB, how much actually fits on the first tape?

BackupExec has never reported capacity or free space acurately, as far as I can remember

[pkh]

Yes. In BE, it is an erase.  If there is an IBM utility to do the formatting, use it and see the result.

The brand of tape does not matter.  It is how the drive handles it.  That is why if after formatting the tapes with an IBM utility, you are still getting 745GB, then you should check with IBM about the discrepancy.  It is a hardware thing.  BE can only report what the hardware tells it.

[teiva-boy]

BE reports back what the tape tells it based on a small ASIC on the tape itself.  That said, BE only reports back what it's told, not BE reading the tape in its entirety to figure out how much space is on it, and how much is available by scanning the tape.  

That said, try a long erase in BE, or even better, use a manufacturer supplied utility to erase the tape.  Both HP, IBM, and Quantum have utilities for this very function.  

Much can be learned here on LTO technology:

http://en.wikipedia.org/wiki/Linear_Tape-Open

[WaltSakir]

I searched the IBM website for a tape erase utility and could not find one.  Can someone please provide me with a link to a LTO Ultrium tape erase utility.  Also can the utility be used on different brands of tapes.  Currently we are using IBM and TDK tapes if this helps.

[Ken_Putnam]

For the tool, see

http://www-01.ibm.com/support/docview.wss?uid=ssg1S4000662

Yes it can be run against any brand of tape

[WaltSakir]

I downloaded the tool and installed on windows server 2008 64bit.   I then stopped all the services in Backup Exec 2010 R2  and started the IBM Tape diagnostic tool and went to the tapeutil section.  From there I tried to open  the device \\tape0 and received the message that Open Device FAILED Errno 1 Incorrect function.  What am I doing wrong?

[WaltSakir]

In addition I tried using the tape library commands and open the device \mediumchanger0 and received the message errno 5 Access is denied

[pkh]

Time to contact IBM?