Two FC10's with extend striping and mirroring on N4000

[Chas Kalsi]

Question is that we have an early N4000 on 2 cpu 360 mhz. We are upgrading to later N4000 series C with 4 * 750 mhz (RP7400).

On the present live server we have the following setup:

The first FC10 ( I will call it FC_A) is connected to fibre adapters to slot 6 (hardware path 0/2) and slot 12 (hardware path 1/0).

The second FC10 ( I will call it FC_B) is connected to fibre adapters on slot 5 (hardware path 0/10) and slot 11 (hardware path 1/8).

The device files for the discs are as follows :

0/2 creates c3t*d*
0/10 creates c5t*d*
1/0 creates c4t*d*
1/8 creates c6t*d*

The new N4000 series C is basically going to be connected to FC_A and FC_B on switch over day. Currently I have on loan 2 identical FC10's to help me build the new server, the Fibre adapter cards are in the same slots as the Live server and the fibre leads are connected in the same way but I am seeing some difference i.e.

on hardware paths and device file eg.

0/2 creates c3t*d* ( fine)
0/10 creates c4t*d* ( different)
1/0 creates c5t*d* ( different)
1/8 creates c6t*d* ( fine)

I am worried that when switch over to the new box with our live FC_A and FC_B we are going to get problems ?? What should I do ? Is it best to rebuild the disc structure again when we connect the new box to the FC_A & FC_B ??

Please advice .... any advice will be much appreciated.

Thanks in advance,

Chas Kalsi.

[Duncan Edmonstone]

Fibre channel hardware paths change - its a fact of life on HPUX.

You can, of course still get at your storage. All you need to do is before shutting down the old server, for every volume group that is on the server run:

ll /dev/vgXX/group
vgexport -p -s -m /tmp/vgXX.map /dev/vgXX

Obviously replacing vgXX with your VG name.

Copy the resulting /tmp/vgXX.map file to your new box and make a note of the device minor number for the group file reported by the ll /dev/vgXX/group.

Repeat for all the other volume groups.

Now turn off your ols system and connect your disks up to your new system.

Then for each volume group:

mkdir /dev/vgXX
mknod /dev/vgXX/group c 64 0xnn0000

replacing 0xnn0000 with the device minor number you notred previously, then

vgimport -s -m /tmp/vgXX.map /dev/vgXX
vgchange -a y vgXX
vgcfgbackup vgXX

Your data is now back on the new disk paths without any problems.

HTH

Duncan