Fred,
I have been using Magstar 3590 with ADSM on MVS for nearly two years
and have just started using Magstar MP in a 3575 with ADSM on Windows NT.
We have had our share of problems with DAT and DLT reliability and have had
NO problems with the 3590 Magstars. Since we've only been using Magstar
MP for a couple months, I can't speak to how reliable it will be in the
long term. I have done quite a bit of reading comparing Magstar MP to DLT
and other technologies and feel that the Magstar employs the best
technology. We have the C model drives in our 3575 library. They have a
maximum transfer rate of 7MB/sec uncompressed 15MB/sec compressed. DLT7000
has a maximum of 5MB/sec uncompressed and 10MB/sec compressed. One
benchmark of my own I can share is I restored a 14GB drive with 32 ~400MB
files in 40 minutes. I will soon be performing tests on more real world
scenarios with lot of smaller files.
Comparing Magstar MP to DLT, the tape in a Magstar cartridge never
leaves the cartridge where DLT threads a leader which, after many loads,
can break off. DLT also writes data to the very edges of a tape causing
the tape edges to wear. MP has a servo track embedded on the media and
never writes all the way to the edge of the tape. If a MP tape head gets
off alignment during a write operation, the servo reader on the drive stops
writing and adjusts. DLT aligns itself during the load of the tape. If it
gets off track during a write it has no way to correct and could overwrite
data. As far a time to the first byte of data there is no comparison, MP
is much faster. This would be very important if you are thinking of
implementing HSM where a user has selected an archived file on a server.
You'll want a tape solution that can reduce that users wait time as much as
possible. That's a few of the technical differences and may be more
detail than you wanted.
In terms of comparing cost I'd simply ask "how much is your data worth
to you?".
As far as the future of Magstar it appears, at this point, to be a
strategic product for IBM. IBM also has formed a partnership with Seagate
and HP on an open tape standard called LTO or Linear Tape Open. LTO will be
based on Magstar MP. Not sure how the standard will be different if at all
from Magstar MP but it might be worth asking your IBM sales rep about it.
Here are some interesting URL's on the Strategic Research website regarding
tape products and Magstar MP. Some are older but the comparisons are still
accurate in my opinion.
http://www.sresearch.com/sp_IBM9810.htm
http://www.sresearch.com/105435.htm
http://www.sresearch.com/105472.htm
http://www.sresearch.com/105405.htm
http://www.sresearch.com/105355.htm
Good luck,
Jeff Connor
Niagara Mohawk Power Corp
Syracuse NY
Fred J Stellabotte <stellabotte AT HAZELTINE DOT COM> on 11/11/98 10:59:48 AM
Please respond to stellabotte AT hazeltine DOT com
To: ADSM-L AT VM.MARIST DOT EDU
cc: (bcc: Jeffrey P Connor/IT/NMPC)
Subject: Should I buy Magstar or DLT ..??
Hi All ...
We are in the final stages of purchasing ADSM ... we were planning to
use DLT (StorageTek 9714), but IBM and one of their vendors is making it
very attractive($$$) to use IBM's Magstar ...
It seems that if I use the StorageTEK 9714 Library with (60 Tapes) I must
purchase
the "Extended Device Support". But If I use IBM's Magstar Library with the
same
capacity (but 240 tapes) I don't have to purchase the Extended Device
support
...
With the quotes I am working with the Magstar Unit is more expensive but
the
total
quote comes out less because of the Extended device support.
Are there any real benefits to using Magstar ..???
What is the average cost of the Magstar Tape vs the DLT tape ..???
Is having a smaller tape a plus with ADSM ...?
Is Magstart really faster in recovery as the Vendor Claims ..???
Will IBM Abandon the technology ..???
Thanks so much .....
-Fred
____________________________________________________________
____________________________________________________________
>| == Fred J. Stellabotte
stellabotte AT hazeltine DOT com
>| == Manager Technical Support
>| == _______________________________________________________
>| == GEC - Marconi Hazeltine Voice:
(516)262-8308
>| == 450 Pulaski Road Fax:
(516)262-8290
>| == Greenlawn, New York 11740 Beeper:
(516)453-4228
_____________________________________________________________
|
