Configure disks already in use for powerpath

[sanjivusa]

Hi,
I am using Sun server and EMC Symm. storage and
Veritas Volume Mgr.
In my Symm. setup all disks were configured for powerpath. I added two more logical devices (cxxtxxdxxsxx)
, sd.conf had already entry so ran drvconfig, formated newly added disks, "vxdctl enable", added disk under Veritas Volume group and finally used these disks for growing my existing volumes.
Here I forgot to configure these two disks under powerpath.
Is it possible to add/configure these two disks under powerpath online ? If possible is there any risk associated ?
Is powerpath recongnize newly added hardware once i reboot my sun box. Will it reconfigure it automatically ?
Please suggest!!!

 

[Chacalinc]

if you reboot the solaris with [tt]reboot -- -r[/tt] the powerpath took all devices, including newly added. To check it out just issue (as root):

[tt]powermt display[/tt]
[tt]powermt display dev=all[/tt]

are all your devices, including the new devs?

if not you can run [tt]powercf -i[/tt] and [tt]powermt config[/tt]

[tt]man powermt[/tt] to see more options.

Cheers.

 

[sanjivusa]

Chacalinc, thanks for your suggestion.
Just to understand better I have following questions -
i) Both added devices are already in use. Is there any
data loss risk in adding these device to powerpath
control now ?

ii) As i said above I already ran devfsadm, and disk has
been already recongnized by OS, then why do i need to
reboot Sun box in reconfiguration mode ( reboot -- -r)?
Is it requirement that powerpath only does rescan the
HBA or added device when SUN box reboot in reconfig.
mode ?

iii) I see two startup file under /etc/rcS.d/S24powerstartup
and S63powershift. S63powershift does following -
any configuration saved in /etc/powermt.custom is moved
to /etc/powermt.custom.0 prior to the execution of
"powermt load" . And then "powermt config" and
"powermt save" commands executes.
My question is -
From where powermt load the file as default file
custom no more exists ? Startup file is not using
command "powercf" . Is "powermt load" scans newly
added device, creates node and later "powermt save"
creates a new custom file entry ?

Thanks,

 

[Chacalinc]

Both added devices are already in use. Is there any data loss risk in adding these device to powerpath control now ?

no, there is no risk in adding this devices to the powerpath control. I'm pretty sure that both devices are already in powerpath control. To make sure issue:
[tt]powermt display dev=all[/tt]

you should see both LUNs in the list.

when a LUN is under powerpath control, you can use either the device as solaris know it (/dev/dsk/cxtxdx) or as powerpath pseudo device (/dev/emcpowerX), both ways will use powerpath.

As i said above I already ran devfsadm, and disk has been already recongnized by OS, then why do i need to reboot Sun box in reconfiguration mode ( reboot -- -r)? Is it requirement that powerpath only does rescan the HBA or added device when SUN box reboot in reconfig mode ?

not really, I told you about [tt]reboot -- -r[/tt] just to add the new devices as disk drives, doesn't matter about powerpath... anyway, it is good to reboot the box in order to get the newly added devices and let powerpath make its job (adding them to powerpath control), but it is not required, just simplicity.

If you add the newly added devices online (via devfsadm) you should run [tt]powermt config[/tt]... i'm not sure about [tt]powercf -i[/tt] since this command is not available in all unix, but -if my memory doesn't fail me- powercf should be in solaris. just in case:

[tt]man powercf[/tt]

I see two startup file under /etc/rcS.d/S24powerstartup and S63powershift. S63powershift does following -any configuration saved in /etc/powermt.custom is moved to /etc/powermt.custom.0 prior to the execution of "powermt load" . And then "powermt config" and "powermt save" commands executes.
My question is -From where powermt load the file as default file custom no more exists ? Startup file is not using command "powercf" . Is "powermt load" scans newly added device, creates node and later "powermt save" creates a new custom file entry ?

From where powermt load the file as default file custom no more exists ?
powerpath doesn't need to load the custom file. This file going to be saved just in case you need an older configuration (in order to use [tt]powermt load[/tt] manually).

Is "powermt load" scans newly added device, creates node and later "powermt save" creates a new custom file entry ?
no, [tt]powermt load[/tt] will load the custom file. it is [tt]powermt config[/tt] the command that will make the powerpath configuration using the existing devices. And yes, [tt]powermt save[/tt] will save the current powerpath configuration.

Again,[tt]man powermt[/tt], specially config, load, save, display. [tt]man powercf[/tt]

Cheers.

 

[sanjivusa]

Chacalinc,
Thanks you very much for your detail info. That will really help me. I checked and found out of 14 devices only 12 devices are under powerpath control using "powermt display dev=all" command.
Also /kernel/drv/emcp.conf file shows device entry for only 12 devices ( not the two devices I forgot to add).

Anyway I will reboot my box in reconfig. mode (reboot -- -r) and hope it should work. I donot want to take any change online when volumes are up and devices are in use. Startup file for powerpath runs before Veritas vol. manager starts.

Thanks again.