Dumps file system information.
dumpfs { FileSystem | Device }
The dumpfs command prints out the superblock, i-node map, and disk map information for the file system or special device specified. This listing is used to find out file system information. Primarily, the dumpfs command is for debugging purposes.
To print the information for /dev/hd4, enter:
dumpfs /dev/hd4
The fsck command, mkfs command.