Hi, Joni.
All of these questions are answerable via risk/benefit analysis and the
answers are all specific to your shop.
We have 2 separate SANs, and each drive plugs into both SANs. Each of our
highly available TSM servers has at least two interfaces with at least one
interface on each SAN, so we can stay available if an interface or an entire
SAN goes down. Our library (STK 9310 Powderhorn) has 2 grippers and 2 arm
motors. This provides us with redundancy within the library itself. This
is pretty expensive, but someone obviously sold the idea that outages were
more expensive than buying the hardware. <Grin>
However, our less available servers have one interface plugging into one SAN
to get to the SAN devices. Each SAN has redundant switches, so a switch
going out won't take down a path, but if an interface or a fibre drop goes
down, these servers will experience an outage. This is cheaper.
If we were a shop that didn't require it, we probably wouldn't have this
level of redundancy unless we had significant "throw-away" money. (And who
as that?) So it all comes down to your expected outages, your projected
cost of outage, and how much your redundancy costs would be, including extra
maintenance, extra administration, etc.
I hope this helps.
Alex Paschal
Freightliner, LLC
(503) 745-6850 phone/vmail
-----Original Message-----
From: Joni Moyer [mailto:joni.moyer AT HIGHMARK DOT COM]
Sent: Thursday, January 22, 2004 4:29 AM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Are 2 interfaces per drive necessary?
Hello everyone!
I was just wondering if it is necessary to have 2 interfaces per drive?
The setup is a Tape Area Network of 24 drives, which haven't been chosen
yet, attached to 2 McData 6064 directors which are then attached to the TSM
server and the LAN-free client servers. Any experiences/suggestions on
this matter would be appreciated. Thanks!
Also, does everyone create an environment with total redundancy and no
single point of failure, such as the library, a single robotic arm, single
connection to the drives, etc. or do you trust the hardware technology?
Thanks again in advance!
********************************
Joni Moyer
Highmark
Storage Systems
Work:(717)302-6603
Fax:(717)302-5974
joni.moyer AT highmark DOT com
********************************
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