Re: SSA Cabling and Adapter problem

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Date:         Wed, 17 Nov 2004 16:26:37 +0100
To: aix-l@Princeton.EDU

Yes: I used Link Verification from the SSA Service Aids.

When I didn't see any disks hanging off ssa6, I ran "cfgmgr -l ssar", (no
change) then cfgmgr.
I also ran cfgmgr again after I'd removed the cables from ports 4 & 5, and
the disks went missing. On both occasions, there was no obvious effect.
With missing disks I didn't want to hang around running extra diagnostics or
anything. I did run diagnostics afterwards but they didn't show any
problems (apart from the broken loops, of course).

Simon Green
Altria ITSC Europe Ltd
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-----Original Message-----
From: IBM AIX Discussion List [mailto:aix-l@Princeton.EDU] On Behalf Of
Simon Marchese
Sent: 17 November 2004 15:13
To: aix-l@Princeton.EDU
Subject: Re: SSA Cabling and Adapter problem

Simon, just to confirm - when you say "when I checked ssa6" you did that
with SSA Link Verification again? Did you run cfgmgr at any stage here?
Simon.

"Green, Simon" <Simon.Green@EU.ALTRIA.COM>
Sent by: IBM AIX Discussion List <aix-l@Princeton.EDU>

17/11/2004 14:49

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Subject
SSA Cabling and Adapter problem

I've got an odd sort of cabling problem.

Following some work to remove an HACMP cluster, one of our servers has been
left with broken SSA loops.

The current configuration has one Advanced Serial RAID Plus adapter
connected to one 7133-D40:
A1 -> Port 9
A2 -> Port 16
B1 -> Port 5
B2 -> Port 4
The drawer is set to BYPASS throughout. So the A loop is fine, but the B
loop is broken, because the cables should have been connected to ports 1 and
8.
(There are actually six drawers, each set up as an independent loop; all are
in the same condition.)
The adapters have fast-write cache.
The server is an S7A with two I/O drawers, running AIX 4.3.3.

I can't see any way of correcting this without making some disks briefly
unavailable. (Running cables between ports 1 & 8 would do it, but I don't
have any short cables.)

There is a seventh adapter in the server, not connected to any disks at all,
so I thought I could use this as a sort of intermediary.
I hooked up it's B ports to ports 1 and 8 on one of the drawers.
When I checked the SSA Link Verification service aid for the original
adapter, (ssa4), it showed a complete B loop, correctly identifying ssa6 in
the middle of it. However, when I checked ssa6 it did not appear to have
any disks connected to it, which worried me somewhat.
Subsequently, when I tried removing the connections from ssa4, the disks
went missing. Everything is mirrored across drawers: I wouldn't have
attempted it otherwise. I put things back the way they were and got
everything recovered swiftly.

So: what should I have done to get ssa6 properly configured so that I could
remove ssa4? (And repeat the procedure for the other five adapters.)
Can anyone suggest an alternative procedure which does not involve making
disks temporarily unavailable?

--
Simon Green
Altria ITSC Europe s.a.r.l.
AIX-L Archive at https://new-lists.princeton.edu/listserv/aix-l.html
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N.B. Unsolicited email from vendors will not be appreciated.
Please post all follow-ups to the list.

• Previous message: Moody, Mark: "Re: Easy one! APARS -vs- Filesets"
• Maybe in reply to: Green, Simon: "SSA Cabling and Adapter problem"
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