We bought a new server with preinstalled RHEL 5. It has RAID 1 and 2 Hard drives of 500 GB capacity. This is what it shows:
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/VolGroup00-LogVol00
3.9G 458M 3.3G 13% /
/dev/mapper/VolGroup00-LogVol05
3.9G 177M 3.6G 5% /home
/dev/mapper/VolGroup00-LogVol04
5.9G 3.9G 1.8G 70% /var
/dev/mapper/VolGroup00-LogVol03
3.9G 137M 3.6G 4% /tmp
/dev/mapper/VolGroup00-LogVol02
7.8G 2.1G 5.3G 29% /usr
/dev/sda3 190M 16M 165M 9% /boot
tmpfs 2.0G 0 2.0G 0% /dev/shm

I usually set up the / partition to the maximum size in all the installations. How do I resize the root partition and others without much of pain ? I tried googling to no avail. I would really appreciate any help.

Looks like you have tons of unused space, so:

• Create a new partition of type 8e (Linux LVM) with the free space using fdisk
• (probably) reboot the machine - to make the partition table readable
• pvcreate /dev/??? use the new partition created
• vgextend the root volume group using the new PV
example: /usr/sbin/vgextend VolGroup00 /dev/sda2
• lvextend the logical volume
example: lvextend -L+15G /dev/VolGroup00/LogVol00
• ext2online - to make the space viewable (may be called resize2fs on RHEL 5)
example ext2online /dev/VolGroup00/LogVol00
• Test for free space - df -h

Do what AlucardZero suggested. Also, he's right, the correct command is resize2fs.

Thanks AlucardZero.

Here is the situation now:
Disk /dev/sda: 499.5 GB, 499558383616 bytes
255 heads, 63 sectors/track, 60734 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System
/dev/sda1 1 9 72261 de Dell Utility
/dev/sda2 10 662 5245222+ 8e Linux LVM
/dev/sda3 * 663 687 200812+ 83 Linux
/dev/sda4 688 60734 482327527+ 5 Extended
/dev/sda5 688 60734 482327496 8e Linux LVM


I am a little confused about the pvcreate part. I am sorry.

so sda5 is new? just run: pvcreate /dev/sda5, then continue

Thanks for being with me.
Now it says this:
Can't initialize physical volume "/dev/sda5" of volume group "VolGroup00" without -ff

And then I forced it like this:

pvcreate /dev/sda5 -ff

Really INITIALIZE physical volume "/dev/sda5" of volume group "VolGroup00" [y/n]? y
Can't open /dev/sda5 exclusively. Mounted filesystem?

I am sorry about this. I decided to start from the scratch and reinstall the RHEL after partitioning as I wanted. Thanks for AlucardZero and JD50.