On each node, the file /opt/mapr/conf/disktab lists all of the physical drives and partitions that have been added to MapR Filesystem. The disktab file is created by disksetup and automatically updated when disks are added or removed (either using the MapR Control System, or with the disk add and disk remove commands).

Sample disktab file
# MapR Disks Mon Nov 28 11:46:16 2011 

/dev/sdb 47E4CCDA-3536-E767-CD18-0CB7E4D34E00
/dev/sdc 7B6A3E66-6AF0-AF60-AE39-01B8E4D34E00
/dev/sdd 27A59ED3-DFD4-C692-68F8-04B8E4D34E00
/dev/sde F0BB5FB1-F2AC-CC01-275B-08B8E4D34E00
/dev/sdf 678FCF40-926F-0D04-49AC-0BB8E4D34E00
/dev/sdg 46823852-E45B-A7ED-8417-02B9E4D34E00
/dev/sdh 60A99B96-4CEE-7C46-A749-05B9E4D34E00
/dev/sdi 66533D4D-49F9-3CC4-0DF9-08B9E4D34E00
/dev/sdj 44CA818A-9320-6BBB-3751-0CB9E4D34E00
/dev/sdk 587E658F-EC8B-A3DF-4D74-00BAE4D34E00
/dev/sdl 11384F8D-1DA2-E0F3-E6E5-03BAE4D34E00