I have a server setup with a RAID 5 using (3) 500GB drives, 1 as a spare so unused in the RAID. So in my mind i start out with 990GB with the RAID 5 in place. When looking at DF or the built in disk space utility i only see a total of about 882GB, how can i find where the 100+GB went? How can i get it back?

I've checked the RAID 5 BIOS and i see all the space.

I've tried looking manually and through terminal commands with no luck.

Filesystem     -      1K-blocks   -   Used Available - Use% - Mounted on
/dev/mapper/vg_web-lv_root
                       838084192  48368700 747153060   7%      /

tmpfs                   12104644       592  12104052   1%     /dev/shm

/dev/sda1               495844      121546    348698   26%    /boot

/dev/mapper/vg_web-lv_home
                       82569904    259136  78116468      1%    /home

    Filesystem            Size  Used Avail Use% Mounted on

/dev/mapper/vg_web-lv_root

                          800G   47G  713G   7%      /

tmpfs                      12G  592K   12G   1%      /dev/shm

/dev/sda1                 485M  119M  341M  26%      /boot

/dev/mapper/vg_web-lv_home

                           79G  254M   75G   1%      /home