Hi all!

I think some information is missing here.
If /dev/sda is ~5GB, then /dev/sda1 contains all of them according to fdisk?
Also df shows that sda1 has ~2G. Where are the missing 3G?
Result of fdisk and df is below.

******************************************************************
bugzilla:/dev# fdisk -l

Disk /dev/sda: 5368 MB, 5368709120 bytes
255 heads, 63 sectors/track, 652 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System
/dev/sda1 * 1 261 2096451 83 Linux
bugzilla:/dev# df -a
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/sda1 2063059 386144 1572093 20% /
tmpfs 518332 0 518332 0% /lib/init/rw
proc 0 0 0 - /proc
sysfs 0 0 0 - /sys
udev 10240 24 10216 1% /dev
tmpfs 518332 0 518332 0% /dev/shm
devpts 0 0 0 - /dev/pts
tmpfs 512000 0 512000 0% /tmp
******************************************************************

bugzilla:/dev# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda1 2.0G 378M 1.5G 20% /
tmpfs 507M 0 507M 0% /lib/init/rw
udev 10M 24K 10M 1% /dev
tmpfs 507M 0 507M 0% /dev/shm
tmpfs 500M 0 500M 0% /tmp
******************************************************************

Also:

bugzilla:/dev# cat /proc/partitions
major minor #blocks name

8 0 5242880 sda
8 1 2096451 sda1

Evidently you have some space on the disk that is not allocated to any partition.

Welcome to LinuxQuestions.
To elorabate on stress_junkie's post sda1 is only 262 out of a total 652 so the entire device is not being used. The missing space is unallocated. You can use gparted to resize the partition but make sure it is unmounted first.