some aix nodes didn,t boot after san switch replacement

rammaghenthar
rammaghenthar used Ask the Experts™
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in a single aix frame some 7 nodes are failing  after san switch replacement, but some other nodes are coming up? What points do i need to check  to make remaining nodes up
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Commented:
Hi,

this looks quite like a zoning problem.

Are you running NPIV adapters? If so, please be aware that you must use WWN zoning on your new switch.

Port zoning will not work, because an NPIV adapter carries several WWNs, so just zoning the port is not enough.

Also please note that the switch port(s) must be made "NPIV" aware during switch setup.

The running nodes might use dedicated adapters or might be connected over a working VIOS.

wmp

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Commented:
thanks wmp ji.   what  is port level zoning ? And wwn level zoning?  as i system admin what task do i need to do? What task san team to do?
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Top Expert 2013
Commented:
Hi,

a SAN zone is a collection of WWNs which can communicate with each other.

There are several ways of setting up such a zone.

WWN zoning means making up such a collection of WWNs to be members of a zone.
The advantage of WWN zoning is that you can plug a given HBA into any switch port, even across trunked switches and the zone will follow the WWN.

A WW(P)N is kind of a MAC address of fibre channel HBAs.

Port zoning means making up a collection of switch ports so that the WWN of any adapter connected to one of these ports will be automatically a member of the zone.
The advantage of port zoning is that you can replace HBAs without worrying, because zoning will not be affected if you connect the new HBA to the same port as the old one.

Now it should be obvious that port zoning will probably produce undesirable results, because a single NPIV HBA can carry several WWNs.
In case of port zoning all these WWNs will be automatically part of the port's zone, which will on one side lead to  blocking some needed communication paths, on the other side to opening paths which are unnecessary or even dangerous.
Live Partition Mobility in conjunction with port zoning will make things even more complicated, because the port on the target system might not be in the correct zone. In case of WWN zoning (and trunked switches, of course) Live Partition Mobility is not a problem, because the WWN will follow the LPAR.

So I really guess that your SAN zoning in the new switch is wrong, the more if NPIV and port zoning are in use.

So tell you SAN team to check the switch zoning carefully. Give them all configured NPIV WWNs (check on VIO with "lsmap -all -npiv") and advise them to use WWN zoning.

wmp

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