How to replace a core san switch for HP-UX 11.31 on-line

[vandevoort]

HP-UX 11V31 EVA Storage .
At a customer
They need to replace the core san switches in the storage san environment . Cisco 32 port into 48 ports
This will result into a domain ID change and also ports on the EVA Storage can and will be different.

Because all systems (Blades 870 and 860) are full operational this will be done on –line , with the core switch 2 path’s will be temporary unavailable.

Does anyone have any experience in this?
What are the risk’s on HP-UX ? Will HP-UX detect the new paths again to the luns after new cores switches ae installed
Or do I need to prepare something, or change/execute after new core switch is available ( ioscan insf ) ?
Who does have any experience in this ??

[Jorge Pons]

Hi

do you have 2 paths from servers to EVA?
do you want to replace 2 fabrics?

The question is to replace only one, with the same ID Domain, while all trafic is for the other one. Obviusly, there is a risk, but if you can do when there is less traffic, coulb be a solution.

Regards, Jorge

[vandevoort]

No the have 4 paths available , we want to replace one switch first , check after switch is operational if all four paths are back again then , replace a while later other core switch.
does HP-UX recognize the path's again after a new switch is installed ??

[Jorge Pons]

Hi

If you access a disk from 4 paths, and you loose one of them, you dont have problems.

When you replace the switch, the domain and port must be the same, and its probably, Im not sure, if it create new device files, you must unplug port, remove it (original and new create with rmsf -H) and plug again.

Regards, Jorge

[Manix]

vgexport using the -p -s -m options for all the VGs on the SAN just for safety purposes.

http://h30499.www3.hp.com/t5/System-Administration/Replacing-san-switch/m-p/4391658/highlight/true#M350337

[Torsten. · Accepted solution]

With 11.31 the device files are no longer dependent on switch domain ID, switch port etc.

Check your pathes with scsimgr, e.g.

# scsimgr -v lun_map

Once the switch is replaced, check again. The system should discover the new paths and use them.

[Benoy Daniel]

In 11.31 each lun got its on WWID. The device files wont even change if you change the switch.

[vandevoort]

Thanks all of you for your response.
Unfortunately we do not have a test environment, for this kind of cases.
I will Inform that they can replace the switch on by one, check in between that all paths are back and available again ..

[hvhari]

As mentioned in one of earlier posts, HPUX 11.31 can manage the change of the san switch without any issue, as the device file is now dependant on the WWID of the LUN.