Adding Brocade switch to Fabric and who "wins"

[Adam Garsha]

I am going to be adding another switch to my fabric and I wanted to re-use a Domain ID that was used long-ago (for a switch that is no longer part of our fabric).

Namely, I have switches at DID 1,3,4,5,6,7. I want to add a switch at DID 2.

My issue is this, if I add a new switch to the fabric, will it upset things because it currently thinks itself is "principle" and since it has a lower DID than most of the other switches?

More to the point, how do the switches in a fabric determine who should run the show with regard to zoning when a new switch is added? Is it a quorum thing (most switches win the fabric?)

Thanks.

[Steven Clementi · Accepted solution]

Adam:

Adding in the new switch shold effectively remove it's status as "principal" and make it subordinate in the existing fabric. Even if it stayed as Principal, it would have to do a fabric merge first and the existing configuration would still be in place.

As for the determining factor as to who gets to be principal, I think it iwas found out a while ago that the switch with the lowest WWID wins the election, if and when it happens.

Furthermore, no "set" of switches win when joining them. The fabrics merge to become 1 bigger fabric. if the merge does not happen, then the switch does not join the fabric.


Steven

[Mark Poeschl_2]

What I would do Adam is completely remove any zoning information in the DID 2 switch and then physically connect it into your existing fabric. This will ensure there are no conflicts during the "merge" - the existing zoning configuration will be blown into the DID 2 switch in its entirety. As for which switch becomes principal (because of lowest WWID) - it doesn't matter. Zoning merge conflicts would have the same effect no matter which switch ended up trying to be principal - which is why I prefer to avoid them altogther.

[Adam Garsha]

HP also had be set "Insistent Domain ID Mode". They argued that I wouldn't get "2", like I wanted, unless I did this.

Looks good. Here is what I did:


switchdisable
configure
fabric->"Insistent Domain ID Mode=Yes"
cfgclear
cfgenable
cfgsave
...
plug-er-in
switchenable
switchshow...
zoneshow...

all good.

[Stephen Kebbell]

Adam,

as Steven says, the switch with the lowest WWN generally becomes principal when a a fabric change happens (e.g. add or remove a switch)
But you can also use the fabricprincipal command on a particular switch so that this switch will become principal with the next change. We have a core/edge fabric topology with 2 core switches per fabric. On both of these switches the fabricprincipal is set to 1, on all others it remains at 0 (default). Beforehand one of our old Brocade 2800 edge switches became principal, as it had a low WWN number. Now it's always one of our core switches (Brocade 48000). The fabricpricipal command is not available on all version of Fabric OS.

You should then perform any zoning changes from the principal switch. ANd also try to ensure that the Fabric OS version is consistent across the fabric, if that's possible. Our 2800s are running 2.6.2c, all other switches are on 5.0.3
I have never used Insistent Domain IDs, we set the domain ID of any new switch before it joins the fabric using the configure command, and it never changes. Also, when adding a switch, we use the same procedure you used:
switchdisable
configure
cfgdisable
cfgclear
cfgsave
plug in first ISL
switchenable
fabricshow
check to see if it merged, and if so plug in any other ISLs

Regards,
Stephen