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Occasional Contributor
Posts: 9
Registered: ‎11-17-2009

Principal Switch Question

Hi,

Today was the first time I have ever merged 2 switches to form a small fabric. I have a quick query with regards to the Principal Switch Allocation that I wonder if you could help clarify.

We have these 2 switches;

dnbuknorssw03:admin> fabricshow
Switch ID   Worldwide Name           Enet IP Addr    FC IP Addr      Name
-------------------------------------------------------------------------
   1: fffc01 10:00:00:05:1e:dd:07:04 10.162.168.113  0.0.0.0        >"switch03"
  10: fffc0a 10:00:00:05:1e:e8:ec:ad 10.162.168.200  0.0.0.0         "switch01"

What we wanted to try and do was get switch01 to be the principal. I understand that by default the switch with the lowest WWN will become the principal and in this case that is switch 03.

When we started the work both switches had fabricprincipal disabled;

fabricprincipal --show
Principal Selection Mode: Disable
Principal Switch Selection Priority: 0

So what I thought we need to do was this;

1) Switch 01 - fabricprincipal --enable -p 0xff -f  to enable the mode and also assign the highest possible priority to this switch.

2) Switch 03 - fabricprincipal --enable -p 0x01 -f to enable the mode and also assign the lowest possible priority to this switch.

We did this before we merged the switches together. But as you can see this has not done the trick. So I must have missed something fundamental here.

Could someone just help me try to understand where I went wrong with this and the best way to get switch01 to be the principal.

Thanks

External Moderator
Posts: 4,974
Registered: ‎02-23-2004

Re: Principal Switch Question

--->>> 1) Switch 01 - fabricprincipal --enable -p 0xff -f  to enable the mode and also assign the highest possible priority to this switch.

--->>> 2) Switch 03 - fabricprincipal --enable -p 0x01 -f to enable the mode and also assign the lowest possible priority to this switch.

--->>> Could someone just help me try to understand where I went wrong with this and the best way to get switch01 to be the principal.

You cannot set more switch in the same fabric as principal at same time

Set in Switch 01 whit the command "fabricprincipal 0" of Disable

and force as Principal Switch 03 whit the command "fabricprincipal -f 1"

TechHelp24
Super Contributor
Posts: 635
Registered: ‎04-12-2010

Re: Principal Switch Question

Andrew,

the big question is why do you want to force a switch to be the principal?

This election will stop the FC traffic flow during the FabricBuild process which takes some seconds.

You have tags for 5100 and 5300 so I assume that both switches are new. In a small fabric like yours with two switches it is not important which switch is the principal.

Best regards,

Andreas

N/A
Posts: 1
Registered: ‎06-13-2007

Re: Principal Switch Question

It is odd, I have the exact same problem trying to merge a DS5100 and a DS300. The DS300 has the lower wwn, but since it will be an edge switch of many, the 5100 is the core, I would prefer to make the 5100 the principal. No matter what I try to merge these 2, it keeps saying the same thing:

Segment: Zone Conflict

no next principal pt

reconfig due to Fabric Segment port blah (ISLs)

I have set the fabricprincipal enable on the Ds5100 and disabled on the Ds300. Even pushed the same zoneset to to both switches so effective zones are identical. Tried disabling and enabling the DS300's, nothing will let them merge. The stupid thing is, they were once merged when the all I had was the Ds300 (added the 5100, then moved all storage/hosts to the 5100, then removed the 300 to relocate it).

Any advice greatly appreciated!

Dave

Super Contributor
Posts: 635
Registered: ‎04-12-2010

Re: Principal Switch Question

check if on one or all switches the defzone set to noaccess.

if so change it to allaccess before you try to merge them.

I hope this helps,

Andreas

Regular Contributor
Posts: 201
Registered: ‎11-24-2009

Re: Principal Switch Question

That part is tricky and not well documented.

As per FC-SW standard, highest value (0xFF) means lowest priority. And in turn, lowest value (0x01) means highest priority. Brocade does it the same way.

To make it worse, any switch that does not participate in Principal Switch Selection games will have priority 0 so it will take over.

Hope this helps,

Linar

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