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Adding extra uplink port to existing SAN Fabric

Frequent Advisor

Adding extra uplink port to existing SAN Fabric

Hi All,


I have an existing Flex Fabric module firmware 3.71 .


I have recently plugged in port X2 of the VC module into our fibre switches.


I have a working san fabric in production but this only had one module from each VC plugged into the san switches.


This was port x1 from each VC interconnect.


so for example


SAN_Fabric_A is made up of Interconnect 1 port x1 goes to fibre switch 1

SAN_Fabric_B is made up of Interconnect 2 port x1 goes to fibre switch 2


The server profiles are set up and running fine no issues.


I would like to add port x2 of each interconnect to their correspnding SAN Fabrics to increase the bandwidth.


Can I do this by simply editing the SAN Fabric and going to the Add port option and adding port X2.


Will this cause any issues ?


Will the current running Server profiles be ok as I am not changing or adding anything but only adding to the san fabric they are already using ?


I can not seem to find a good answer to this anywhere.




Respected Contributor

Re: Adding extra uplink port to existing SAN Fabric

I can't imagine that it would.  I have asked multiple times to different people at HP about how those connections are assigned to the server.  I am told that it happens when the server starts.  So they all have X1 right now.  As that gets congested and you restart servers you will start to see them grab X2.


What is your setting for Login Restribution?  I believe that Automatic kicks in if there is a link failure and at boot.


Are your servers setup Active/Active for storage?  As a precaution that's what I'd do - that way if things go sideways the connection out of bay 2 will be live and passing data so there shouldn't be a disruption.

Matthew Ingram
Regular Advisor

Re: Adding extra uplink port to existing SAN Fabric

I am by no means an expert as I have just been working on a FlexFabric POC. I just did this the other day. I have two C7000 stacked and had one 8GFC on port one to our Cisco MDS. Bay one one to one fabric and bay 2 to the other. We simply plugged them in and I added them to the san fabric in VC. After a few seconds the ports came up and the san fabric status was all green. We left the default manaul login distbution when creating the fabrics so if you want to start using both links you'll have to click to manually redsitribute the logins.


If there is an issue....say someone plugs the other end into the wrong fabric it will isolate the port and not use it (ask me how i know ;). Its tricky to figure out as the fabric just shows in a degrated state.

Trusted Contributor

Re: Adding extra uplink port to existing SAN Fabric

I agree with both.

You CAN add extra connections on the fly.
You either need Automatic Login Redsitribution on (FlexFabric) or you need to do it manually.

The other thing I wanted to clarify if there is no ISL type trunking going on. VC simply distributes the logins evenly among all uplink ports. So 8 servers with FC and 2 uplinks = 4 servers per uplink. This is done because ISL trunking requires a lot of work on cross platform compatibility which frankly sucks in the FC world. So to keep it simple and easy, VC just spreads out the connections upon FLOGI into the Fabric and uses NPIV so it can act as a fan out device.