Originally posted by: lapfrank

Hi All,

I'm preparing to migrate some servers from vscsi to pass-thru NPIV. I am planning to have the SAN team move the exact LUNs from vio1/vio2 to those two VWWN through NPIV.

My question is on the partition itself.. right now, let's say I have hdisk0/1/2/3/4 that are part of datavg.

I have installed powerpath (those are symmetrix luns). When I varyoff/exportvg the old LUNs, and discover the new ones through NPIV, they will show up as "hdiskpower" devices.

Will the importvg actually recognize the data on hdiskpower devices or will it try and import the "hdisk" devices under the hdiskpower?

Never tried that before!

Thanks for your help,
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Originally posted by: MarkTaylor

Yes, it should do .. all the data you need is in the VGDA .. so, as long as you get the disks presented up correctly, then an import should work ok ..

HTH
Mark Taylor
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Originally posted by: SystemAdmin

what you're doing is known as p2v ("physical to virtual") although in this case it's more like v2p.

there is a redbook on the topic. search for the qouted string above.

D.
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Originally posted by: lapfrank

Thanks Mark!

I checked on a current server with hdiskpower, and it looks like the readvgda command reads the same data from both the hdiskpowerX and then both associated hdiskX under it. Hopefully, when I use NPIV, when the hdiskpower device is created, it will copy the same VGDA info on it.

The redbook is also useful, although it doesn't talk about EMC devices, only about MPIO managed disks.
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Originally posted by: PontiacGeronimo

I guess you will boot your client LPARs on SAN (via vfcs) so you should consider native AIX MPIO instead Powerpath.

as far as I remember Powerpath does not allow to:

• "bosboot" not switching powerpath off for that time (again activation requires reboot I think)
• do mksysbs and them restore it properly (I think it must be always reinstalled after os recovery)

I think AIX "hates" hdiskpower devices.

any idea?
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Originally posted by: lapfrank

I don't know if AIX hates hdiskpower devices.. but I do agree with you. That is why I'm keeping VSCSI for my rootvg, passing those two disks through VIO1/VIO2 then mirroring on the OS side.

Seems simplier to manage to me than to have to take care of EMC filesets, powerpath versions, etc. when I upgrade AIX or need to restore a mksysb.

I'm only planning on migrating to NPIV my data volume groups. Not sure how most people do it though.

Also, the problem with using MPIO only is that I can't get round-robin on EMC devices. From what I understand, EMC wants you to buy Powerpath. Why would you use Powerpath if native MPIO could load-balance hdisks, right?
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Originally posted by: mmveiga

I have used PowerPath with NPIV for two years, my company had to request certification from both IBM and EMC for PowerPath 5.3, PowerPath 5.5 is now officially certified.

For bosboot to work, you have to run "pprootdev off", according to EMC support load balancing and failover still works, but now AIX has the PVID in the hdisk not the hdiskpower devices.

Never knew that mksysb is not supported, I had successfully restored mksysb images and did not have to reinstall PowertPath.

Regards,
Marcelo.
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Originally posted by: PontiacGeronimo

for sure you need to reinstall powerpath when you migrate you OS to newer release.

Q1: when you disable powerpath for bosboot or mksysb, do you need to reboot your system to get powerpath devices working again? what is the difference when your system works on hdisk (plane EMC) devices and when on hdiskpower? (you write: ...load balancing and failover still works...) Is it ok to have in use hdisk devices and not hdiskpower devices? how it affects HACMP cluster environment which operates on hdiskpower devices? (eg. diskhb communication lines).

Q2: all the time you need to setup hdisk devices on bootlist (hdiskpower are not supported). what if you have on your virtual environment with vfcs'es more then 5 hdisk's (paths) to your rootvg's disks? as far as I know AIX bootlist supports only 5....

Q3: are you familiar with "EMC Enginuity™ software"? in the install guide EMC writes:
Considertions for Symmetrix storage
In a Symmetrix environment, booting from a PowerPath device is
supported in Fibre Channel environments that include specific
versions of EMC Enginuity™ software. The E-Lab Interoperability
Navigator provides details. Contact your EMC Customer Support
Representative for information about installing Enginuity software.
Do you have such software installed on your systems boot from SAN?

And a statement about mksysb master image:
"Installing PowerPath as part of a mksysb master image
If you are creating a master site mksysb backup image for installing
complete host images (including PowerPath software on target
systems), you must completely remove all hdiskpower devices and
the powerpath0 device from the source system from which the
mksysb image will be created."

It is really problematic to disable powerpath (pprootdev off) and reboot a production system to remove all hdiskpower devices to be able do such system image.
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Originally posted by: mmveiga

I did not say you don have to reinstall PowerPath when performing AIX upgrades, I said that you don need to reinstall after restoring a mksysb image.

When you run "pprootdev off" the PVID that was associated with the EMC powerpath device from rootvg shows in the AIX hdisk devices that compose the paths to that power device, there is no need to reboot the server PowerPath is still doing failover and load-balancing, only the PVID is no longer on the EMC powerpath device.

It does not affect the EMC powerpath devices that are not part of rootvg, so no impact on HACMP or disk heartbeat networks.

You have to set in the bootlist all the AIX hdisk devices that represent the paths for the EMC powerpath devices, and yes the maximum devices you can define is the limit for the bootlist.

I am not familiar with EMC Enginuity.

The information about creating master images is for cloning, right ? Does not apply to mksysb created to be restored in the same host, I already did that without any issue.

Regards,
Marcelo.
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