While the thread is getting longer and longer, I still see some more to
comment.

Richard already gave the answer - TSM will split the file into pieces and
put each chunk on a tape. So the size of file compared to cartridge
capacity is not an argument. The number of tapes depends on tape
technology used (is it 3590B, E or H) and actual compression ratio.
The actual problem is with speed - 3590E and H drives can write at 14 MB/s
native = 50,4 GB/hour. 500 GB means up to 10 hours and you have to rely
heavily on compression. If you introduce large diskpool (as some
suggested) it will not help with speed but will force you to buy another
500 gig of disks. Diskpool can help for zillions of files totaling 500 GB
but single files over several GB are very good candidates for
direct-to-tape.
To best of my knowledge z/OS does not support any LTO. Thus LTO solution
would not work without adding an open system TSM. We have to look only
through mainframe drives or consider some sort of UNIX.
Mainframe drives - we may choose between IBM 3590 and StorageTek 9x40.
When IBM start shipping next drive based on widely advertized last year 1
TB cartridges, it might be good. But for the time being 3590s are
providing rather low capacity and are rather slow. The alternative is
called STK 9940B and *is* available on the market delivering native
capacity of 200 GB and data transfer rate of 30 MB/s (108 GB/hour). This
is not an ad, it is the reality, and I am not affiliated with StorageTek.
I know there are StorageTek people monitoring this list and am nearly sure
there are no IBM SSD people.
UNIXes - if open system is introduced, LTO is viable alternative. You have
to consider TCO - new box, LTO library/drives/media, some more licenses
*and* the effort to maintain one more TSM server + its set of tapes to be
tracked offsite. The latter have to taken seriously as many mainframes on
this list admit tape management on mainframes is far better than open
systems'.
BTW: Zoltan, HP's & Seagate's implementation of LTO-2 is 30 MB/s native
while IBM is publishing 35 MB/s in their specs. I've not verified it as
till recently we have not sold Ultrium 2.

Zlatko Krastev
IT Consultant






Tim Brown <tbrown AT CENHUD DOT COM>
Sent by: "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>
07.08.2003 21:43
Please respond to "ADSM: Dist Stor Manager"


        To:     ADSM-L AT VM.MARIST DOT EDU
        cc:
        Subject:        bACKING UP A SERVER WITH 500gb


i am using using tsm with primary disk storage pools (zos 3390's) and
secondary storage pools
3590's

new server i installed has a file that is over 300gb's, changes daily
i have had to exclude the folder that contains the file till i can find
a storage medium that will have enough capacity

what are other folks doing to backup this amount of data


Tim Brown
Systems Specialist
Central Hudson Gas & Electric
284 South Ave
Poughkeepsie, NY 12601
Phone: 845-486-5643
Fax: 845-486-5921