PowerPath Kernel Updates

I do the following when updating the kernel of a RHEL system that uses PowerPath to HBA mount a Clariion.

1. Prepare system to be rebooted without the SAN
   When the system is rebooted with the new kernel the SAN won't be there so make sure you don't try to use it:
   • Stop any processes that uses the HBA mounted LUNs and remove their startup scripts from /etc/rc*.d for after the reboot.
   • Umount any HBA LUNs and then comment out their entries in /etc/fstab
2. Install your new kernel
   Explicitly tell up2date to get your new kernel. E.g.:

    up2date -i kernel-hugemem
   

   You might need to do an up2date --configure and set pkgSkipList (option 20 from the list) to an empty string. You might wish to undue this step later so that you don't get a new kernel with each up2date (otherwise you might have to follow these steps again when you're not ready).
3. Update PowerPath for the new Kernel

    rpm -Uvh --replacepkgs EMCpower.LINUX-5.0.0-157.rhel.i386.rpm
   

   After doing the above PowerPath should start without a emcpmpx module error. Note that you might need the x86_64 RPM. The RPM comes from EMCpower.LINUX.*.tar.gz.
4. Undo what you did in step 1 (in reverse order) and reboot.

Of course if I was really cool I would just use the Free software MPIO instead of PowerPath.