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Occasional Contributor
Posts: 5
Registered: ‎08-22-2008

Changing from interop to native change Hardware Path of HP-UX

Hi,

here to you the problem.

I've a fabric with 2x3200 and 1xDS200 in ISL with McData 24M2. McData fabric was the interop mode set on the whole fabric. Now I want to change to native mode with DS200 and new DS300.

The question is: is there any changes on domain ID? I mean that without Mcdata mode there isn't offset (60 ex) and I'm wondering which domain ID the host will see.  I tried to simulate the offset setting in native mode a Domain ID 90+X, but even if the nsshow shows correct domain, the HP-UX lose the paths.

HP-UX v1 and v2 is affected from domain ID.

Thanks,

Mario

Valued Contributor
Posts: 931
Registered: ‎12-30-2009

Re: Changing from interop to native change Hardware Path of HP-UX

If seen that behaviour on HP-UX before but only with tapedrives and we used an multipath solution (SecurePath/AutoPath) from HP.

At that time I was told that its known behaviour with tapedrives or non securepath/autopath systems.

To put it in other words;

1 leave the interop untouched

or

2 be prepared to rescan for your disks at reattach them.

Should you use LVM VG's you could try a vgscan to get them back, but don't lmow the details by head as its to long ago i used LVM commands.

Occasional Contributor
Posts: 5
Registered: ‎08-22-2008

Re: Changing from interop to native change Hardware Path of HP-UX

Hi,

you are right but this HP-UX (and AIX) behaviour is not limited to tape drive but extended to all target (storage, tape drive). The special files of volume are base on internal hardware path, and the H/P is based on a part of the address SAN (FCID)

Brief review (from an HP forum)

FC Addressing Syntax:
HBA.Domain.Area.Port.Bus.Target.LUN
Resolving the above example:
HBA = 0/6/2/0
Domain = 0/6/2/0.1 (1 is Domain ID nothing but a FC Switch Domain ID)
Area = 0/6/2/0.1.0
Port = 0/6/2/0.1.0.0
Bus = 0/6/2/0.1.0.0.0
Target = 0/6/2/0.1.0.0.0.0
LUN = 0/6/2/0.1.0.0.0.0.1

If I change from McData mode to Native mode I lose the offset (96 dec) and all luns become invisible. If I change the ID simulating the offset (original ID + 96), does anything change from the SAN view? Doesn't it?

Valued Contributor
Posts: 931
Registered: ‎12-30-2009

Re: Changing from interop to native change Hardware Path of HP-UX

In theory from the hosts perspective, the fabric appears to be offline  (as a switchdisable is recurred) and a few moment later comes up again with the same (DID + offset) new calculated DID, this should work.

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

Re: Changing from interop to native change Hardware Path of HP-UX

Hello Mario Contestabile,

HP-UX prior to 11.31 uses all parts of the 24-bit FCID of the Target port, so once you move away from McDATA mode you should consider the following changes:

= Domain ID is decreased by 0x60 (96); you've already addressed this with Domain ID adjustment.

= the lowest, or Port byte (better known as ALPA) is set to 0x13 in McDATA mode, but is normally 0x00 in Native mode. To address that, use PortCfgALPA command.

As an example, a FCID 0x61ZZ13 in McDATA mode becomes 0x01ZZ00 in Native mode; you fix 0x01 with domain offset, 0xZZ is the same as it's physical port#, and 0x00 you turn back to 0x13 with portCfgAlpa.

At the end you'll have the very same FCID as you had in McDATA mode, so HP-UX Hardware Paths will remain the same.

Hope this helps a bit,

Linar

P.S. Another option could be to reconfigure every host with vgexport/vgimport or application-specific modifications.

Occasional Contributor
Posts: 5
Registered: ‎08-22-2008

Re: Changing from interop to native change Hardware Path of HP-UX

Hi Linar,

it's correct. In this case I haven't any McData switches  in my fabric but only Brocade and all FCID adresses have XXYY00. I fixed new DID with 60+XX and all works without problem.

So defintively I can confirm:

if you migrate from McData mode to Native mode in a Brocade fabric, you'll not have impact on hosst view if:

1) fix the offset using a manual offset of 60 (exa)

2) if the ALPA is set to 13, you have to fix it to 13 with portCfgAlpa

This is referred overall to HP-UX (lower of V3) and AIX (lower 6.X)

Thanks Linar,

Mario

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