topic Re: Changing discs hardware path in Operating System - HP-UX

Changing discs hardware path

PSS SYS ADMIN — Mon, 11 Oct 2004 07:44:19 GMT

Hi everyone,
I'll have to move the discs in SAN attached to an hpux11.00 box from a path to another.
What are the operations to do on the box to see the same remote disc?
Can I know before the change the future paths that will have the discs?

regards...
PSS

Re: Changing discs hardware path

Sunil Sharma_1 — Mon, 11 Oct 2004 07:50:43 GMT

make sure all disks are available and the mv /etc/lvmtab to some other name and run vgscan. It will recreate lvmtab file abd then you can do vgchange. all old volumes will be visiable to you

Other way is export volume group with map file and the import after path changed.

Sunil

Re: Changing discs hardware path

Colin Topliss — Mon, 11 Oct 2004 08:22:32 GMT

Hi,

Can you clarify a few things?

Are you saying that you are having to move disks to another fibre channel (ie moving a fibre from one port to another) or are you saying that you have to move SAN attached disks to another system entirely?

What array are you using?

You can work out in advance what the paths will be by looking at the instancing on the FC HBA you are going to connect the disks to EG:

The following extract shows a Tachyon adapter that has the ext_bus instance number set to 32 - all LUNS that appear off of this array interface will start c32.....

ba 12 9/0/14 lba CLAIMED BUS_NEXUS Local PCI Bus Adapter (782)
fc 2 9/0/14/0/0 td CLAIMED INTERFACE HP Tachyon XL2 Fibre Channel Mass Storage Adapter
/dev/td2
fcp 7 9/0/14/0/0.97 fcp CLAIMED INTERFACE FCP Domain
ext_bus 32 9/0/14/0/0.97.8.19.0 fcparray CLAIMED INTERFACE FCP Array Interface
target 7 9/0/14/0/0.97.8.19.0.0 tgt CLAIMED DEVICE
disk 362 9/0/14/0/0.97.8.19.0.0.0 sdisk CLAIMED DEVICE HP OPEN-E
/dev/dsk/c32t0d0 /dev/rdsk/c32t0d0
target 8 9/0/14/0/0.97.8.19.0.1 tgt CLAIMED DEVICE
disk 363 9/0/14/0/0.97.8.19.0.1.0 sdisk CLAIMED DEVICE HP OPEN-E
/dev/dsk/c32t1d0 /dev/rdsk/c32t1d0
target 9 9/0/14/0/0.97.8.19.0.2 tgt CLAIMED DEVICE
disk 364 9/0/14/0/0.97.8.19.0.2.0 sdisk CLAIMED DEVICE HP DISK-SUBSYSTEM
/dev/dsk/c32t2d0 /dev/rdsk/c32t2d0

When moving between systems, you can use re-instancing to ensure that the target HBA has the same setting as the current (we do this quite often in clusters).

Hope this points you in the right direction!

Col

Re: Changing discs hardware path

bhavin asokan — Mon, 11 Oct 2004 08:29:25 GMT

hi,
i assume the following situation.

1) your disk array is connected to hp box directly.
2)you want to connect it through SAN switch

or

1) you want to connect diskarray connected through one san switch to another.

both case disc path will get changed.
before changing if it is possible take a ignite backup.and create backups of important files like /etc/fstab , /etc/passwd ,...

the procedure is.
1. create map files for all the VGs

vgexport -s -p -v -m vg00.map /dev/vg00
vgexport -s -p -v -m vg01.map /dev/vg01
...
...
etc

2. connect the disk array through another path.

3.run ioscan to see all the disks are available with the new path.if disk files are not created automatically run insf -e
command.

4.vgexport the VG which is using disk array( before this you should note down the minor number of that VG.)

5.create a new folder for that VG in /dev
make the group file.(assuming vgxx is the old vg)

mknod /dev/vgxx/group c 64 minor number

vgimport -s -v -m vgxx.map /dev/vgxx

repeat this for all vgs

-p is used for preview mode so that it will not remove the VG when creating map file.if you omit this it will remove the VG entry also from lvmtab file.

-s is used for shared mode .this option will include the VGID in the map file. at the time of importing you don't have to mention the pvs if you are using this option.
system will automatically findout the disks(which is connected to system)which is having same VGID and it will get added to specified VG .otherwise you should have to manually specify the pvs in that volume group.

-m used for specifying map file.if you are not using map file , at the time of vgimport it will create the lvs with default naming convention. ie. lvol1 ,lvol2 ,lvol3 ,.... in this order. if you are having some different names for lvols for your convenience like sales , admin (which you may have identified/mounted for using by specific depts) will not be imported on the same name with out map file.(map file contains the existing lvol names)

at the time of importing you can specify
first vgimport -s -p -v -m vgxx.map /dev/vgxx for checking .

regds,

Re: Changing discs hardware path

PSS SYS ADMIN — Mon, 11 Oct 2004 08:34:30 GMT

I want to connect diskarray trough the same SAN changing the switch model (so the hardware path it will change)

Re: Changing discs hardware path

bhavin asokan — Mon, 11 Oct 2004 09:19:13 GMT

hi,

take the map file.
if path is changing then do the procedure.

regds,