nicoroy123_15c2b9

41 Posts

3563

July 7th, 2009 11:00

What is the exact role of the EMC PowerPath Windows service?

Hi, is there any impact of restarting the powerpath windows service?
Does it mean I loose path redundancy or access to the Symmetrix volumes?

Or it is simply used by the Gui monitor?

Thanks

Responses(7)

nicoroy123_15c2b9

41 Posts

0

July 7th, 2009 11:00

Would it simply stop the multi-pathing or stop the entire access to the volumes?

dynamox

1 Rookie

•

20.4K Posts

0

July 7th, 2009 11:00

do not restart PowerPath service, since windows devices are claimed by PowerPath ..all IO goes through them.

nicoroy123_15c2b9

41 Posts

0

July 7th, 2009 12:00

This is interesting. We have multiple Windows servers that actually boot from SAN, on a Symmetrix. So it means Windows, when starting the boot sequence, access the volume on SAN and start booting, then somewhere in the boot process, the EMC Powerpath service kicks in to make the volume multi-pathed and redundant.

So this is why I was wondering how critital is the service itself. I thought that the service only allows the OS to see a multi-pathed drive as one instead of two, but would not prevent the os to see it if restarted.

Message was edited by:
nicoroy123

dynamox

1 Rookie

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20.4K Posts

0

July 7th, 2009 12:00

not exactly sure ..i know for sure that when i accidentally restarted PowerPath on a development windows 2003 box ..it blue screened.

Mich

86 Posts

1

July 7th, 2009 16:00

As far as I am aware the service has little to do with the actual functionality of the operation of PowerPath. What it does do, is assist in the monitoring and logging of PowerPath messages, and works with the PowerPath monitor, and Powerpath Administrator application.
As per the "PowerPath for Windows Installation and Administration Guide" .. for Windows 2008...the functionality has changed

"The traybar monitor program now communicates to the PowerPath service where it previously communicated directly with the kernel driver. This means that if the PowerPath service is disabled or fails to start, the traybar monitor will not function and an error will be displayed."

nicoroy123_15c2b9

41 Posts

0

July 8th, 2009 12:00

This is what I think too.
I know the service has been restarted here on a dev server. The goal was to activate a licence number to make PowerPath Active/Active. The PPAdmin was still showing unlicenced until we restarted the service.

We didn't see any impact on IO, not even an error msg in the Windows Event Log beside info eventw saying that the service has been restarted and the licence activated.

I don't want to say that this is the right procedure to activate a licence but it worked. I am still wondering what are the real impacts on multi-pathing functionalities when the service is stopped or restarted.

B

bencrookEMC

30 Posts

1

July 8th, 2009 13:00

Powerpath has lower level filter drivers under device manager in the scsi section and system devices section. these are the major components of powerpath. like the previous person mentioned the ppath windows service is a different component.

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