20203   zERR READ FAILURE

Source:  NSS, Common Layer, General Storage System

Explanation:  An attempt to read a low-level asynchronous block failed.

Possible Cause:  A media failure occurred, such as one or more sectors on the disk cannot be read.

Action:  Retry the operation. If the error persists, reboot the server. Replace or reformat the disk, and then restore the affected areas from backup.