SSA Loop Help 1

[vtaixer]

Hi
we have an 7133-D40 on one host using two adapters. There is one loop on this drawer. We need to add another drawer.
What is the recommend config for one host using two drawers and two adapters and keep one loop? I'd like one loop for hot sparing.
Thnks!

 

[DukeSSD]

http://www.redbooks.ibm.com/abstracts/sg245750.html

Just bung it inline with the existing drawer:

ssa0/portA1 > drawer1/port1 | drawer1/port16 > drawer2/port1 | drawer2/port16 > ssa1/A2 > ssa1/A1 | ssa0/portA2

Or stick it on the B ports with just the same config as you have on the existing drawer.

Or is your existing drawer already split across the A and B loops?

 

[vtaixer]

Thanks for your reply
The B ports are used for another drawer in another loop.
Question: With the above config,if an adapter goes down, does that mean there is only one port active?

 

[p5wizard]

What about:

[tt]
ssa0/portA1 > drawer1/port1 | drawer1/port16 > ssa1/portA1 ssa0/portA2 > drawer2/port1 | drawer2/port16 > ssa1/portA2

ssa0-A1 - D1/1..16 - ssa1-A1 - ssa1-A2 - D2/16..1 - ssa0-A2
[/tt]

If one of the adapters fails, the remaining adapter's two ports each still see 16 disks

(been a long time since I last used SSA)


HTH,

p5wizard

 

[DukeSSD]

Yes you would only have a single link if an adapter failed and the adapters were connected together.

p5wizard's idea is better but you should go A1 - A2 - A1 - A2 not A1 - A1 - A2 - A2 because the code can get a bit confused during device discovery during boot otherwise.

ssa0-A1 - D1/1..16 - ssa1-A2 - ssa1-A1 - D2/16..1 - ssa0-A2

AFAIK it does not matter which way round you use the ports on the drawer but try to keep the card ports in the loop in a 1212 order.

 

[DukeSSD]

Oh, and beware, hot spare disks can only be used for arrays or disks on the same loop.