A Guide to Success with the A5814A-003 SCSI-FC Router

The BEST option is to use Device Port settings, FC Switch Zoning and even LUN
Security to prevent a "Windows" system from seeing your MPE/iX Disk Volumes.
Any O.S. can cause this to happen but "Windows" systems tend to be the most
aggressive. Your best protections are:
A) Limit each Device Port to only one Type of O.S.
B) Use FC Switch Zoning to limit the number of ports that are Zoned together.
C) Where possible, LUN Security can help prevent problems.
"Multiple OS Access" can cause the following problems:
o ":DSTAT ALL" suddenly shows device as UNKNOWN.
o Session or System Hang (due to inability to complete I/O).
o System Abort (due to Disk I/O failures in critical places like XM).
o "Random" data corruption, especially in Volume Label areas.
Rule #1: Plan, Plan, Plan.
As with ANY data center deployment the best path to success is a careful
design your FC-SAN in advance. Planning really should be "Rule #0" but most
people already know that so their eyes glaze over and they stop paying
attention. Hopefully, if your eyes haven't glazed over I have fully
impressed upon you the simple fact that this ain't so simple. Good planning
will really truly save you major headaches.
Following Rule #0 your goal is to create a STABLE "view" for a Router
before you start trying to configure MPE/iX disks volumes. If you are
FORCED to expand an existing configuration it is much easier and safer to
expand into virgin territory of previously unused Device and FC Switch Ports.
It can be much harder to accommodate "just one more LUN on a port" than you
might think.
Make sure you understand the number of Systems, SCSI HBAs, Routers, Disk
LUNs, Device Ports, Storage Devices and the resulting number FC Port and FC
Switches to tie it all together (limit of no more than two levels of switches
between Router and Device Port). Ideally you should also allow additional
Device and Switch Ports to handle expansion or to correct a mistake in your
original design. (A Spreadsheet is a really great tool to accomplish this)
A) Create a list of all Systems and HBA/Routers that will be connected.
B) Create a list of the desired number/size of LUNs per HBA/Router.
(recommend Device LUNs <8GB in size no more than 15 per HBA/Router)
C) Create a list of Device Ports -- minimize the number of Routers per Port!
D) Create list to allocate each Disk LUN to a device PORT
E) "Merge" A-D into one list.
(Where you have more than on HBA/Router per Device Port you must then
have an FC Switch to "join" these connections).
F) Merge into "E" the list of all FC-Switch Ports.
G) Note the Zoning required to minimize the number of Routers on each
connection.
H) Determine the number of FC Switches base upon number of Ports required.
I) From G-H Document the Zoning for each switch.
Your result should be a document that can tell you which MPE/iX LDEV
corresponds to which Storage Device LUN AND what path you follow to get there AND who else
shares this same path.
Once the planning activities are complete. Implementation can follow:
J) Make sure you have all Device, Switch, Router Documentation.
(NSS SPOCK)
(New router document)
K) BEFORE YOU MAKE A SINGLE CONNECTION Make sure ALL devices have up-to-date
firmware. Check NSS Streams device for current recommendations for Router,