5400R VSF - Redundant management cards
07-10-2016 11:04 PM
I'm looking at deploying VSF on a pair of 5400R switches.
I'm hoping to clarify a few points that aren't entirely clear in the deployment guides / manuals:
- If the active management module is removed or completely fails in one chassis - will the remaining management module allow both chassis to continue to function?
- If a second management card is installed in a chassis, this gets disabled when VSF is configured. Will this second card come online in the event of a failure or is it essentially a cold spare?
Re: 5400R VSF - Redundant management cards
07-12-2016 06:52 AM - edited 07-12-2016 09:07 AM
Hello Scott, Interesting questions your ones. On the Aruba VSF Configuration Guide is stated that:
"VSF will disable a second Management module in any 5400Rzl2 chassis that has 2 Management modules installed"
So it looks like that Nonstop Switching mode or Warm Standby mode, if enabled (AMM+SMM), is going to be automatically disabled (and SMM placed in disabled state = Offline status) when VSF is enabled.
On the ArubaOS-Switch Management and Configuration Guide for K./KA./KB.16.01 published this June is stated that:
"The Aruba 5400R switch has two management module (MM) card slots available. Hewlett Packard
Enterprise recommends that you have only one MM for each Aruba 5400R switch when VSF is
enabled. A second MM, if present, will be shutdown. Hewlett Packard Enterprise recommends
that the second MM be removed from the chassis to prevent it accidentally becoming active."
Written in that way it seems that if VSF is enabled and a second MM is physically installed but not enabled on the Commander chassis (condition that could be easily true when Nonstop-Switching or when Warm Standby aren't enabled on that chassis, considering that if one of the two is enabled the second MM would gain the Standby status instead of its original Offline status) then when the actual AMM fails there is the non-remote possibility that the second MM, although in Offline status, can become active taking the role of the new AMM...and this action would be very disruptive with respect to VSF...so I read that HPE advised to physically remove the second MM to be sure.
It's not clear to me if having a second MM in Offline status will be enough instead of physically removing it: I found that "in the Offline mode, the MM cannot take over when the Active MM fails over" is written on the ArubaOS-Switch guide above.
Interesting to see that the second MM is placed in Offline status once the VSF is enabled (see attached screenshot taken from the above guide)...so will be interesting to know how (and why) eventually an Offline MM came back to life and become the new AMM if the current AMM fails. It shouldn't be possible.
What happens then when considering all these doubts in the light of the VSF Commander/Standby roles?
It really looks like the presence of the second MM is more an issue than a potential future processing enhancement to the VSF deployment.
Sorry to add my doubts to your ones...