400GB Tapes only using 200GB space.

[David_Camburn]

Hello

I've kind of 'ended up' in charge of the back-up at my place of work.

My boss very kindly bought some 400GB tapes because our full weekend backup runs onto two 200GB tapes.

Put the new tapes in labelled them, went home for the weekend...and came back to find that that the machine is only using them as 200GB (compressed) tapes.

How can I set the tapes to use the full capacity? I asked my boss and he think that's the maximum for our drive, a ULT3580 TD2

Many thanks.

[Steve_Hett]

The drive has to support the capacity of the tape you purchased.

If you have tapes that will do 200 GB (native) I would assume you have LTO2 tapes and if you purchased a tape that will do 400 GB (native) I would assume that you purchased LTO3 tapes.

The ULT3580 TD2 does not support LTO3 tapes. Generally LTO drives are backwards compatible though.

[David_Camburn]

The tapes are HP Ultrium C7972A's I think they are LTO2.

From what I've found on the net they run at 200 native, 400GB compressed (though I think that later is a little optimistic as it's 2:1 compression)

There is an option to select tape types. I don't recall seeing LTO 2 but I'll go back and take another look.

[David_Camburn]

Nope, list of LTO2 tapes ends at 100GB.

Is there a way of updating the list of tapes, does anybody know?

Thanks.

[Sharvari_Deshmu]

Hello,

If it is 200 GB native and 400 GB compressed you will need to use compression.

Please see the technote:

Backups fail to get double the amount of the native capacity recorded to a media, even when hardware compression is being utilized.

http://support.veritas.com/docs/199542

Thanks,

[David_Camburn]

Hi, there.

I've double checked the entries listed in those technotes but all the hardware compression options are active.

I'm not expecting a full 2:1 ratio, but at the moment the backups are sticking doggedly at <200GB.

[aravind_kondapa]

Does your hardware support hardware compression?
Try using software compression and hardware compression and compare the two.
What kind of files are you backing up (already compressed files or not)?

You can also have a look at the compression ratio on the devices tab when you select your device.

NOTE: If we do not receive your reply within two business days, this post would be marked assumed answered and would be moved to answered questions pool.

[Ken_Putnam]

I'm not familiar with your hardware, but I;ve seen some that have a jumper that must be set before HW compresion is availalbe.

Have you tried a run specifying SW compression only?

[David_Camburn]

I'll give the software compression a go, cheers.

[Gauri_Ketkar]

Hi David,

Update us on the same and revert for any further Query
Hope this will help you


Thank you
Gauri

[David_Camburn]

Slightly embaressing (but hey, we learn by our mistakes *cough*)

Tried the software compression and the back ups are running through quicker. So, that's a plus.

while doing some more reading up in the help section I realised that the 'Available Capacity' is in raw data. I played around with the columns and have found the 'Bytes Written Column' The two pretty much add up, so it was working okay afterall.

So, my thanks for your help, and my apologies for wasting your time.