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MSA1000 Active/Standby Configuration with Two Integrated SANswitches

BRYAN DELOS
Occasional Contributor

MSA1000 Active/Standby Configuration with Two Integrated SANswitches

HP customer has a dual-controller MSA1000 running firmware 5.20 active/standby, with two 2/8 FC switches integrated into the rear of the MSA chassis. I have researched many sites and can't find definitive answer to my inquiry about how data flows inside the MSA1000.

Each MSA controller has a 2/8 SANswitch directly behind it. For example, if controller#1 (right-side when viewed from front) is active and controller#2 is standby, can any I/O flow through the SANswitch behind standby controller#2? That is, does each integrated SANswitch (or single-port I/O module for that matter) only serve the controller directly in front of it? Or, does I/O pass through both integrated switches no matter which controller is active?
4 REPLIES
Víctor Cespón
Honored Contributor

Re: MSA1000 Active/Standby Configuration with Two Integrated SANswitches

Each controller is connected ONLY to the switch behind it.

At any given moment, there's traffic only through one switch and one controller. If something fails on the path between the server and the MSA, the multipath software changes to the other path (other HBA port, other SAN switch, other MSA controller).

The active MSA controller is indicated by the 7th LED on the top row of LEDs.
BRYAN DELOS
Occasional Contributor

Re: MSA1000 Active/Standby Configuration with Two Integrated SANswitches

Thank you for your reply. Perhaps you can make some sense out of the continuing strange behavior of this MSA1000 (see first post in this thread for configuartion description).

Both controllers are running firmware 5.20, which MSA documentation says is active/stand-by firmware. But the front panel (LEDs and display) and the CLI output disagree about the current role of each controller. The active/stand-by LED (top row, seventh from left or second from the right) is on steadily on BOTH controllers all the time. The display may show both controllers "redundancy active, active controller" at the same time. How can they both be active if they are running firmware 5.20?

At the same time the CLI (connected serially to either controller) shows one controller active and one controller standby. However, run the "show this" and "show other" commands a few minutes later and both controllers are reported as standby, even though I/O is continuing to servers.

Interestingly, the "show this" and "show other" is as follows:
"Supported Redundancy Mode: Active/Standby Asymetrical Active/Active
Current Redundancy Mode: Active/Standby (emulated)
Current Role: Standby"

Is 5.20 really active/standby? What is this asymetrical active/active? Is that why both active LEDs are on?
BRYAN DELOS
Occasional Contributor

Re: MSA1000 Active/Standby Configuration with Two Integrated SANswitches

Addition to my most recent post - forgot to mention that both controllers have been replaced (one at a time), and the wierd behavior did not change.
Torsten.
Acclaimed Contributor

Re: MSA1000 Active/Standby Configuration with Two Integrated SANswitches

The answer is

Current Redundancy Mode: Active/Standby (emulated)

It's in fact kind of active/active and emulates active/standby.

Hope this helps!
Regards
Torsten.

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