Patent ID: 7418624
Filing Date: 2008-08-26
Classification: G06F

Abstract:
1. A method for controlling system switching in a hot standby system in which an active computer and a standby computer share a storage, the method comprising the steps of: recording in a storage area, when a write I/O request for the storage is made, information about the I/O request currently processed; verifying information recorded in the storage area by use of the standby computer when a failure occurs in the active computer; and recovering the storage when write is currently processed as a result of verifying the information, wherein, when a write I/O request for the storage is made, a notification about a start of the I/O is transmitted to the standby computer and the standby computer receives the notification about the start of the I/O to record in the storage area, information indicating that the I/O is currently processed, wherein, when the I/O request is completed in the active computer, a notification about a completion of the I/O is transmitted to the standby computer, wherein, when a process of the I/O request is completed in the active computer, the information recorded in the storage is deleted.