FreeBSD includes checks in the file system to avoid writing data to damaged sections of the hard drive. Generally this prevents minor problems. Hard drives also include a system to automatically map around bad sectors without operating system intervention. However, the file system consistency check and interactive repair (fsck) program can be used to repair hard drive problems in single user mode. Running this process can increase system efficiency and reduce future issues. Be sure to set aside several hours for the process to run, particularly for multiple drive systems.
Restart the computer in single-user mode. When the boot menu appears, select Option 4: "Boot FreeBSD in single user mode."
Type the following command to see the system partitions:
Make a note of the partition identifiers. For example, "/dev/ad0s1d" is the first partition on the first disk. Write down the identifiers for all the system partitions.
Type the following command to check the partition:
fsck -fy /dev/ad0s1d
This will check and repair any problems. Run the command for each of the system partitions. Replace "ad0s1d" with each partition identifier. The command must be run separately for each partition.
Restart the system after running fsck.