Hard disk does not show in finder

Question

WE had a system failure with our server instance a month back and since then, one of my internal HD's will not show in finder. It's also causing carbon copy pro to fail when trying to find it. I have verified it can be seen in the disk utility and from a terminal prompt. I rant this to confirm:
{ diskutil list; echo; diskutil cs list; } | open -f -a TextEdit  
No matter what I do, i cannot see it. Verify and repair in disk util come up saying it's okay. I have selected show HDD's in finder preferences. A possibly related side effect is that my users, who can browse this over the network, cannot search in the directory.
Any help you can lend would be helpful.
OSX version 10.8.4
TC

Answer 1

Not partitioned - part of a raid. Was initially formatted, yes. THis has been in production for a couple of years and just dropped out. "THIS DISK" is the disk that vanish. I renamed it for forum purposes.
Results:
/dev/disk0
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *1.0 TB     disk0
   1:                        EFI                         209.7 MB   disk0s1
   2:                  Apple_HFS basecampHD              999.3 GB   disk0s2
   3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3
/dev/disk1
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *1.0 TB     disk1
   1:                        EFI                         209.7 MB   disk1s1
   2:                  Apple_HFS HD2                     999.9 GB   disk1s2
/dev/disk2
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *1.5 TB     disk2
   1:                        EFI                         209.7 MB   disk2s1
   2:                  Apple_HFS THIS DISK               1.5 TB     disk2s2
/dev/disk3
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *1.5 TB     disk3
   1:                        EFI                         209.7 MB   disk3s1
   2:                  Apple_HFS TTHIS DISK.Backup        1.5 TB     disk3s2
/dev/disk4
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:        CD_partition_scheme                        *217.8 MB   disk4
   1:              CD_ROM_Mode_1 TSIXL-320W              189.7 MB   disk4s0
/dev/disk5
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:     FDisk_partition_scheme                        *3.0 TB     disk5
   1:                  Apple_HFS ServerTime              3.0 TB     disk5s1
No CoreStorage logical volume groups found