Hello Folks

Back ground - I am not very familiar with Linux LVM and RAID system and I am basically trying to achieve one RHCE cert, with the intention of clear conception on what I learn. I am familar with daily Linux commands.

I have 1 disk with 3 partition namely /dev/sda, dev/sda1, /dev/sda2 (attachment).

1. How to get the size of each partition in fdisk cmd?
2. Why the cmd pvdisplay does not show all 3 partitions? (pvdisplay means physical volume display, so it should dsplay me all partitions in my disk as I know a partition can serve as a physical volume)

BR//R

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Looking at the fdisk output you posted I see 2 and not 3 partitions (/dev/sda1 and /dev/sda2). /dev/sda is the disk itself, and not a partition.

/dev/sda1 has a linux label and probably holds the basic linux system.
/dev/sda2 has a LVM label and is used as such.

The 2 /dev/mapper/... entries you see are LVM related. Both reside "inside" /dev/sda2 and that is why you only see 1 physical volume ("partition").

You might want to have a look at these links:
- Logical Volume Manager (Linux)
- Logical volume management
- Logical volume manager