Yura Pismerov wrote:

Teresa Biehler wrote:

Hi,



For the folks that are using AIT-3 tapes, what kind of capacity are you
seeing?  The specs say 100GB/260GB, but I was interested in some real
world numbers.

Your question is technically incorrect.
I hope yo realize that the answer really depends on what type of data
you back up.

We've just started using them and are seeing tapes being marked full at
130GB-170GB.  I'm trying to determine whether this is an example of real
world not living up to the specs or if we have a problem that needs to
be resolved.



Thanks.

Teresa

We've been backing up with compression in various forms for a decade.
I can tell you from our experience that 50 % - 60 % has been most
typical of our compression ratio.   I don't think I actually said that
clearly.   I think you should expect to get 150 to 160 gb on an AIT-3
tape.  On rare occasions, 170 GB.. I've NEVER seen any real-world
compression that looked like
those AIT-3 claims.   I'd be most interested in knowing if anyone has.
Then I'd know that we're doing something wrong.
Our data is largely binary image data from microscopes, and scanning
devices of various kinds.   Our network is gigabit backboned with
a number of gigabit-capable computers.   Our Networker server generally
claims to be running at about 11-12K KB per Sec  per drive on a good day
which is fast enough to keep the drives moving, isnt it?

                                       Matt Temple

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=============================================================
Matthew Temple                Tel:    617/632-2597
Director, Research Computing  Fax:    617/582-7820
Dana-Farber Cancer Institute  mht AT research.dfci.harvard DOT edu
44 Binney Street,  ML105      http://research.dfci.harvard.edu
Boston, MA 02115              Choice is the Choice!

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