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I have a server running RHEL 5.5 with EMC PowerPath installed. Due to the security requirement, I had to upgrade the kernel to a newer version. Unfortunately, I was not aware of the impact of the upgrade on EMC PowerPath. After the upgrade, the server cannot access to the EMC volumes, and refuses to boot with the local file system with read and write permissions. I have reverted back to the older kernel, but the problem persists.

So, I am stuck. I am not able to change /etc/fstab to remove the partitions on EMC storage, and I am not able to stop the loading of PowerPath kernel modules.

What are my options without resorting to re-install the OS?

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up vote 1 down vote accepted

You haven't added much in the way of details, but it's very possible that the boot process failed due to the powerpath issues, which means your filesystems are still initially mounted as read-only.

If you can get to a shell of some kind, but your filesystem is read-only, try this :

mount -o remount,rw /

(where / is the filesystem you want to remount). This will let you make changes etc. After you've finished, run sync to be sure you've flushed any changes to disk, then reboot.

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This works perfectly! Yes, the PowerPath modules are not working properly. So, I have comment out kernel modules in modprobe.conf. Now I can boot up the system into run level 3 and with write access to local file systems. The next problem is how to sort out the mess in PowerPath kernel modules. I get "Device or resource busy" where running modprobe to load the modules manual. Strangely, all the ko files are still in the current path. – kjloh May 26 '11 at 3:26

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