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Re: How many nodes does 7400 can fail at same time?

Posted: Sat Sep 21, 2013 6:16 am
by Architect
@Cleanur, Richard:

I was not aware 2.3.1 allowed node reboots. This is an eyeopener for me. So on that one, agreed. I was not taking the older software versions into account. Apologies for that.

On the dual node failure in version 3. Just read your own explanation again, a situation where you have to thank heavens above for the fact your 3PAR didn't crash on a dual node failure is simple not an acceptable solution. In other words: The 3PAR is not build for dual node failure, so just don't let it happen, it will go wrong.

On the rebooting part. I've witnessed an occasion where a node in the other node pair was rebooted, during the outage of node in the first node pair, and the V-class 3PAR panicked. Luckily it was a POC setup so no impact, but for the technical part it does not matter.

I don't know why HP is a bit difficult about being clear this. It is not a defect, nor a shame. Other vendor solutions (EMC, etc) are neither build to survive a double component failure.

Re: How many nodes does 7400 can fail at same time?

Posted: Sun Sep 22, 2013 1:45 am
by Richard Siemers
They do seem to keep it on the down low. Back when I first discovered this "mechanic" I felt a little disappointed, perhaps misguided by the promise of "Active Mesh Architecture". However, I now understand the distinction that "Active Mesh" applies to the front end LUN ownership, not the back end PDs.

Re: How many nodes does 7400 can fail at same time?

Posted: Wed Sep 25, 2013 4:45 pm
by dtcorbett
I am getting ready to put a 7400 into service shortly. We will include a 2 controller failure test when we do our fault tollerance testing. Making sure to remove one controller from the 3,2 group and one from the 0,1 group.