jschiwal is right on making sure that the drive has been mounted in the files system, if you did partition the drive during installation then you can point your Apache Directory Path statement to that location as
bathory has stated.
To verify that your drive has been mounted you can use either df or du -h this will list out all mounted partitions. If the drive is not mounted then you will need to make sure that the file system has "discovered" the drive. You can accomplish this by looking to the following set of folders:
/dev/disk/
by-id
by-path
by-uuid
these are on most all linux distros but not always. I usually look to the by-id folder
this is a partial printout:
ls -al /dev/disk/by-id/
total 0
drwxr-xr-x 2 root root 540 2011-11-01 22:19 .
drwxr-xr-x 6 root root 120 2011-10-31 17:32 ..
lrwxrwxrwx 1 root root 9 2011-10-31 02:28 scsi-SATA_ST9320320AS_5SX5KNG2 -> ../../sda
lrwxrwxrwx 1 root root 10 2011-10-31 02:28 scsi-SATA_ST9320320AS_5SX5KNG2-part1 -> ../../sda1
lrwxrwxrwx 1 root root 10 2011-10-31 02:28 scsi-SATA_ST9320320AS_5SX5KNG2-part2 -> ../../sda2
lrwxrwxrwx 1 root root 10 2011-10-31 02:28 scsi-SATA_ST9320320AS_5SX5KNG2-part3 -> ../../sda3
lrwxrwxrwx 1 root root 10 2011-10-31 02:28 scsi-SATA_ST9320320AS_5SX5KNG2-part5 -> ../../sda5
lrwxrwxrwx 1 root root 10 2011-10-31 02:28 scsi-SATA_ST9320320AS_5SX5KNG2-part6 -> ../../sda6
lrwxrwxrwx 1 root root 10 2011-10-31 02:28 scsi-SATA_ST9320320AS_5SX5KNG2-part7 -> ../../sda7
lrwxrwxrwx 1 root root 10 2011-10-31 02:28 scsi-SATA_ST9320320AS_5SX5KNG2-part8 -> ../../sda8
lrwxrwxrwx 1 root root 9 2011-10-31 02:28 usb-Generic-_Multi-Card_20071114173400000-0:0 -> ../../sdb
This print out shows that I currently have only 1 hard drive installed to the machine I am on at this time. If I had 2 drives in this machine it would show sda & sdb(SATA) or hda & hdb(IDE/PATA) and so on.
If you see a second drive "sdb" that is not mounted then you can do the following to "temporarily" mount the drive:
(THIS IS ONLY AN EXMAPLE)
mkdir /media/hdd2
mount /dev/disk/by-id/scsi-SATA_ST9320320AS_5SX5KNG2-part8 /media/hdd2
To add this drive to your file system so that it is auto-mounted when the machine is booted then you will need to edit the fstab file in /etc
For better instructions and a good reference point please visit the following:
http://www.yolinux.com/TUTORIALS/Lin...HardDrive.html
And as always Google can be a good tool as well...