Need help getting EMC PowerPath working in RHEL 6.2

From: Lynn Dixon 
I have a RHEL 6.2 64bit install thats running on a Cisco UCS blade. I have
an EMC Symmetrix VMAX LUN that is given to the machine and it has 4 FCoE
multipaths setup. I installed the OS using "basic storage" and did a
standard run level 3 install.
Redhat recognized the multipaths and just setup dm multipaths
automatically. The machine ran fine with no probs.

Then I decided to install the latest PowerPath .rpm (got 5.6 from the
powerlink website today). So, I commented out everything in
/etc/multipath.conf, and disabled the multipath services from running.
Rebooted, and then I installed the PowerPath .rpm. It ran, no errors, so I
did the license registration. Heres the kicker, I an run powermt list
dev=all (I think thats the command) and it will succesfully show me all of
my FcOE paths, so I thought it was golden. I did powermt save, and rebooted.

Poop hit the fan. RHEL will boot, go through the lower numbered inits, and
even mount and fsck the LVM volumes I am using.....but, once it gets to the
PowerPath service in init, it kernel panicks, and just refuses to boot at

The only way I knew to get it back was to boot to resuce, and move the
powerpath scripts from /etc/init.d to /root and reboot. Any one else come
across this? It know it has to be a simple fix...or I hope.


=============================================================== From: Reed Gregory ------------------------------------------------------ EMC Powerpath is very picky about the exact kernel version needed. For example, pp 6.5 supported RHEL 6, but maybe not RHEL 6.2. I used to use it for some oracle databases with RHEL 4 and it always such a pain to upgrade kernels. It was a multiple boot process with one boot into single user mode to re-setup the powerpath. I have been using linux native multipathing with EMC Clariions over Fiber Channel now for several years and am much happier. With new systems, I have experimented with powerpath and always came back to mpio. We are now running Oracle Linux and I use mpio with it as well, although Oracle's customizations to the dm-mulitpath packages in OL 5 give me headaches. The multipath devices (/dev/mapper/mpath*) are only loaded after it tries to mount my drives, so I have to not mount the drives on boot, but after initial start up. Why do you want to use EMC PowerPath verses the native linux mpio anyway? Reed -- Reed Gregory

=============================================================== From: Lynn Dixon ------------------------------------------------------ Well supposedly, you can't do load balancing in the native mpio in linux. Or that is the reason that I have gotten from our storage guys. We have 4 FCoE paths to this one disk and they are wanting to load balance across each path instead of just simple failover. I would much rather use native multipath as long as I could prove that load balancing worked and worked as well as powerpath.

=============================================================== From: Dave Brockman ------------------------------------------------------ -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Don't know about FC or FCoE, but MPIO iSCSI does load balancing like a champ, I have the traffic graphs on the Interfaces to prove it. This is OpenFiler talking to ESXi. Regards, dtb -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.17 (MingW32) Comment: Using GnuPG with Mozilla - iEYEARECAAYFAk9/TygACgkQABP1RO+tr2RxywCeLOBVfzAWB2bWdgUUz7Lty/Nu YzkAoLumYpQ4v1jqtR3U+RDgK0E1ZBen =XY6B -----END PGP SIGNATURE-----

=============================================================== From: Lynn Dixon ------------------------------------------------------ Well one would think that FcOE would be similiar since its treated like a regular path. I need to clarify, These are actually fiber channels and not FCoE. I made a mistake when I typed that last email... for some reason FCoE was on my mind.

=============================================================== From: Reed Gregory ------------------------------------------------------

=============================================================== From: Dave Brockman ------------------------------------------------------ -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 I need better toys :) I actually didn't have to *do* anything on OpenFiler to make it work, other than assign IP addresses to all the interfaces. Add the IP Addresses in ESX swiscsi, change the L/B to Active/Active, and it was off to the races. Regards, dtb -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.17 (MingW32) Comment: Using GnuPG with Mozilla - iEYEARECAAYFAk9/WysACgkQABP1RO+tr2Q10wCgkWGmBf76kd8BIwhPFElcbgV4 Bh4An3r6PKDEgE02m8yRM3j1g3HkN9DG =hmHj -----END PGP SIGNATURE-----