I habe two hard disk in a RHEl box.I want to convert one of the hard disk to raw disk. Already linux file system is present in the hard disk.Please suggest some method
dd bs=1024 if=/dev/zero of=/dev/sdXX
Use fdisk and delete all partitions, then create a single partition of some type that Linux does not automatically use.
I'm not really sure what you mean, do you want a raw disk, a raw partition or an empty partition?
... and don't have an entry in /etc/fstab for it.