Estimated Capacity with LTO3

[edv_edi]

Hi!

We have got a new TS3500 (3584) with three LTO3-drives. Our old library is a 3583 with three LTO1-drives. Now I have to move data from the old to the new library. I altough have to move data from different disk pools (random access).

I am using the MOVE DATE command in following way:

"MOVE DATA "volume_name" STG="new stg" RECONS=Yes [when the old pool ist sequential]

At the beginning the estimated capacity of the new volume is 745 GB what seams to be alright. But almost all the tapes go in status "full" with 398,3 GB. But I thought it should be able to store about 800 GB at LTO3 tapes!

Here ist the definition of the device class:


Device Access Strategy: Sequential
Format: Drive
Device Type: LTO
Estimated capacity: blank

What is going wrong? Do anybody have an idea?

Thanks for help in advance!

 

[Harry_Redl]

Hi,

what your "q drive f=d" says?
Do you see it can write Ultrium3C (compressed) format? Do you have compression enabled on the drives (not in TSM)
Seems to me it can store only the native tape capacit (400GB) now ....

Hope it helps

Harry

 

[alimirza]

As Harry suggested make sure that in the device class for the LTO3 drive, the format parameter is set to ULTRIUM3C (from your output it seems that you have it set a DRIVE). This will enable compression on the drive and you will get better capacity. I am using LTO3 drives and in case of TDP for oracle backupws, getting over a terabyte on one tape. In most cases the amount stored one one tape is around 700 - 900 GB.

Regards

 

[edv_edi]

HI!

I think I have got the bottom of this problem! We use the client compression and so the data are allready compressed, when they arrive the drive. And double compression is not able. When I understand the administrator manual correctly, TSM is not able to shows the estimated capacity of client compressed data correctly.
How ever, it seems as if it works correctly, or am I wrong?

Much thanks for your posts! They brougt me on the right track!

Rainer