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)
Depends on how the drive is attached.
ATA/SATA drives should normally be detected on bootup. Look into the boot log (
There should also be a list of recognized partitions for all partitioned drives under
For hotplugged drives (e.g. USB) it depends on how the distribution manages them. Usually modern distros use udev (older might use hotplug or hald). The log is configurable, either a separate log under
The sg_* utilities might also be useful:
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.