Question: So I have a server that has a few harddrives in it, all formatted and mounted. However I'm told there is another drive attached to it. How do I find out what drives are attached? How do I find out the device filename for this new drive (that's not mounted)

Answer: 
`fdisk -l`​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​
The sg\_\* utilities might also be useful:

```
$ sudo sg_map -i
/dev/sg0  /dev/sda  ATA       WDC WD5000BEVT-2  01.0
/dev/sg1  /dev/scd0  Optiarc   BD ROM BC-5500S   1.83
/dev/sg2  /dev/sdb  ATA       WDC WD5000BEVT-0  01.0
/dev/sg3  /dev/sdc  WD        PP III Studio II  0817

```

There are lots of other commands in the sg utilities such as sg\_scan, sg\_readcap and so on.

Also if you are booted from a redhat/centos cd you can switch to an alternate console and use the "list-harddrives" command to show disks attached to the system.