primary path change

[nanan]

one of my systems using FC interfaces to XP128
the system is having 2 FC crads, while i checked the load balancing of I/O, i found that too many lvols assigned to one of them, so i wanted to change the primary path of some disks to alternative path.

I issued a command " pvchange -s /dev/dsk/cXtXdX" which was in alternative path device.

but i have experienced a strange thing that just within 10~13sec the path recoverd to the perviouse path.
i couldn't change the path

anybody can help me!!

the system has not any error messages

[Peter Godron]

Hi,
please have a look at:
http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=1042661

Please only execute if you a certain what you are doing.

[Sandy Chen]

Hi Nanan,

You wanted both of the fibre to be used, then what you have to do is:

for example:
vg01
/dev/dsk/c10t5d0
/dev/dsk/c10t5d1
/dev/dsk/c10t5d2
/dev/dsk/c12t5d0
/dev/dsk/c12t5d1
/dev/dsk/c12t5d2

# vgreduce /dev/vg01 /dev/dsk/c10t5d1
# vgextend /dev/vg01 /dev/dsk/c10t5d1

and so on and so forth

regards,
Sandy

[melvyn burnard]

rather think about using
vgreduce
to remove a primary link, this makes the alternate link become the primary
and then use
vgextend
to add in the alternate link again

[freddy_21]

pvchange is a temporary solution, if you reboot the server, your path will be back to original. vgreduce and vgextend is a permanent solution


thanks
freddy

[nanan]

Thanks for all answers!!

But i aready know what you suggested.

Actually what i am saying that after i chaged the path to the alternate one with pvchange commend, for a while chamged path become primary path, but soon recover to the original path automatically.

if i use "pvchange -s /dev/dsk/CXtXdX",
primary path changed and
the path is maintained till reboot the system, isn't it?



even i didn't reboot and any action to the system, as i mentioned,

[sathish kannan]

Hello Nanan,

What's is the error message you are getting on the syslog? Also did you try pvchange without any I/O i,e by deactivating the volume group?


Regards
Sathish

[nanan]

the messages inthe system's syslog are here!!

I've tested the same command on another systems and i got a different results:
recovering to the priveous path and never

could you tell me, the reason why there were such diffrent results...


thanks

[nanan]

the messages in the system's syslog are here!!


I've tested the same command on another systems and i got a different results:
recovering to the priveous path and never

it might be related with patch level or other things

Could you tell me, the reason why there were such diffrent results...


thanks

[Khashru]

Just do a vgreduce of the existing primary path. Then do a vgextend with this path. It will change the order of path.

[nanan]

vgreduce and vgextend can change the path