If I come across a system that uses a label in /etc/fstab instead of a device like /dev/sda1 how do I go about finding out which label is associated with which partition. For instance in an /etc/fstab there is a line like this:

Label=/logs /var/log ext3 defaults 1 2

How do I go about finding out exactly which partition on the disk is associated with that label ? Is there a map kept someplace ?

I never seen that before
try
stat /dev/disk/by-label//logs/var/log

"ls -al /dev/disk/by-label" - by-uuid works similarly if you happen to be unfortunate enough to stumble across that.

The forward slash doesn't look like a legal character. However by mounting by label or uuid, the fstab entry will be valid even if you repartition the drive, or if the device is external and gets a different device node the next time you plug it in.

You can get the label, uuid and filesystem information using the "udevinfo" program. You don't need to run it as root.
For example, if you what the information for the device & filesystem for /dev/sda5:
udevinfo -q env -n /dev/sda5

There are other options besides (-n) such as for using the /sys/ filesystem, the that type of query doesn't use the /sys/ part of the directory name so tab completion doesn't work.

Thanks. unfortunately the machine I am working with does not have udevinfo (udev) installed. However I believe tune2fs should work in this fashion:

[root@esx7 root]# tune2fs -l /dev/sda1
tune2fs 1.32 (09-Nov-2002)
Filesystem volume name: /boot
Last mounted on: <not available>
Filesystem UUID: eb1cfd0f-4f0a-4994-8ad2-eabbff766bb3
Filesystem magic number: 0xEF53
Filesystem revision #: 1 (dynamic)
Filesystem features: has_journal filetype needs_recovery sparse_super
Default mount options: (none)
Filesystem state: clean
Errors behavior: Continue
Filesystem OS type: Linux
Inode count: 26104
Block count: 104391
Reserved block count: 5219
Free blocks: 75027
Free inodes: 26070
First block: 1
Block size: 1024
Fragment size: 1024
Blocks per group: 8192
Fragments per group: 8192
Inodes per group: 2008
Inode blocks per group: 251
Filesystem created: Sun Feb 10 03:10:52 2008
Last mount time: Mon Oct 20 18:18:55 2008
Last write time: Mon Oct 20 18:18:55 2008
Mount count: 71
Maximum mount count: -1
Last checked: Sun Feb 10 03:10:52 2008
Check interval: 0 (<none>)
Reserved blocks uid: 0 (user root)
Reserved blocks gid: 0 (group root)
First inode: 11
Inode size: 128
Journal UUID: <none>
Journal inode: 8
Journal device: 0x0000
First orphan inode: 0

If you don't have udev installed, then the /dev/disk/by-* links won't be created either and you need to stick to the normally named devices instead of auto created links to then same devices. The udevd daemon is what auto creates the device links.