File System Validation
In addition to performing file system repair, the fsck
utility validates that the data on disk has no problems. Traditionally, this
task requires unmounting the file system and running the fsck
utility, possibly taking the system to single-user mode in the process. This
scenario results in downtime that is proportional to the size of the file system
being checked. Instead of requiring an explicit utility to perform the necessary
checking, ZFS provides a mechanism to perform routine checking of all
inconsistencies. This feature, known as scrubbing, is
commonly used in memory and other systems as a method of detecting and
preventing errors before they result in a hardware or software failure.