Home Compute Mid-plane is replaced on our blade enclosure

Mid-plane is replaced on our blade enclosure

by Philip Sellers

Last night, we undertook replacing our mid-plane in the blade enclosure that had problems last month.  It was the first recommendation from HP support after several hours of working with various teams, but both our internal team and our HP field service guys didn’t feel it was the cause.  Turns out, we may have been very wrong with our initial hesistance, but I’m getting ahead of myself. 

After a month of continued support and working the case, we escalated the case to a level where an engineer reviewed all the steps, troubleshooting, and case information to ensure nothing had been missed and to help diagnose the issue.  He came back to the original conclusion – that after all else was eliminated, the mid-plane must be the culprit.  So, we scheduled the replacement. 

The actual hardware replacement went smoothly and took less than an hour to complete.  The midplane is a lot more bulky the I expected when I first saw it.  It is a single piece of hardware with interconnects on both sides that connect blades to interconnect bays, power sources to power consumers and LCD display to the logic.  But, I guess I was surprised that it was a good 2 to 3 inches thick.  In my mind, I expected a single piece of copper sitting in the middle – yes I realize now that’s stupid.  

Something interesting occurred after replacing the mid-plane.  Apparently, Virtual Connect did not see the system serial number that it expected and so it reverted to its default configuration.  So, word of advice to anyone replacing a mid-plane.  Leave your VC modules ejected so that you don’t lose your domain configuration.  From talking with support, Virtual Connect needs constant communication with the OA to function (another dependancy we were not aware of).  The serial number stored reported by the OA from the enclosure is also very important to VC.  Its part of the configuration file for VC.  It all makes logical sense, but it was not spelled out in the support document detailing the mid-plane replacement.  

After unsuccessfully attempting to restore my backup for the Virtual Connect domain, I opted to build it from scratch by hand.  It took about an hour and half to do for my 5 blades, but I feel better about it.  I am still worried about not being able to restore my VC domain configuration, but I attribute that problem to the hardware replacement.

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