HBA Multipath 1

[Mag0007]

Hi:
Running AIX 4.3.3, with 2 HBAs going into an EMC frame.
I am not using EMC PowerPath software. How can I check if I have multiple paths for redundancy?

TIA!

 

[Gloups]

you can't have redundancy without powerpath. The only thing you can do is to set your bootlist with all the logical views of your bootdisk to boot on one of them not depending of your disks availability.

If you lost the logical view of your booted disk, your system will crash even if you'll still able to boot with the other path

 

[Mag0007]

so, what is the point of having 2 HBAs? Other then performance.

I just aquired this server, and the admin did not have any documentation on it.

So, If 1 HBA goes down, the data will be inaccesible?

 

[Gloups]

yes untill you reboot, if your two HBAs are pointing on the same Luns.

With your two HBAs you can restart your system even if one of them or one of the path is crashed

 

[RMGBELGIUM]

2 HBA's is also good for redundancy.We have on our AIX 2 FC's to access our storage, and if one fails, disks are still accessible, but only over reduced number of paths( your errlog wil get spammed, but that's the least of one's worries.)

rgds,

R.

 

[Mag0007]

okay, is redudancy only there if you have power path instaled?

 

[p5wizard]

That depends, you can have redundancy without PowerPath, if you have MPIO (Multi Path I/O) device driver which is built in to AIX (from 5.2 onwards I think). But it is not officially suported by IBM with all the possible Storage boxes, and it is not supported by the Storage vendors on all their boxes and all their firmware levels...

But you do need to have some sort of MP software or device driver, just having 2 FC adapters doesn't cut it.


HTH,

p5wizard

 

[Mag0007]

p5wizard:

good post, as usual.