Lost I/O hang detection

AIX can detect system hang conditions and try to recover from such situations, based on user-defined actions.

Because of I/O errors, the I/O path can become blocked and further I/O on that path is affected. In these circumstances it is essential that the operating system alert the user and execute user defined actions. As part of the Lost I/O detection and notification, the shdaemon, with the help of the Logical Volume Manager, monitors the I/O buffers over a period of time and checks whether any I/O is pending for too long a period of time. If the wait time exceeds the threshold wait time defined by the shconf file, a lost I/O is detected and further actions are taken. The information about the lost I/O is documented in the error log. Also based on the settings in the shconf file, the system might be rebooted to recover from the lost I/O situation.

For more information on system hang detection, see Managing system hang.