Patent ID: 8806081
Filing Date: 2014-08-12
Classification: G06F

Abstract:
1. A method to issue a statesave command from a multi-path host system to attached storage, comprising: dynamically switching to at least one of a plurality of active paths of the multi-path host system for automatic failover protection and issuing a statesave command upon detecting the inaccessible device; determining a tolerance time for a host and an application operable on the multi-path host system for tolerating an inaccessible device thereby setting a timeout parameter using the tolerance time, including at least determining an application tolerance time for tolerating an inaccessible device for each of a plurality of applications in association with the multi-path host system application; anticipating which application or host is relevant for a particular situation for determining the tolerance time; setting the timeout parameter using a predetermined threshold time by taking into account the application tolerance time determined for each one of the plurality of applications, and if the multi-path host system includes a subsystem device driver (SDD) the timeout parameter is set using a new command in the SDD, wherein the SDD is a pseudo device driver that supports multi-paths residing in multi-path host system having a device driver; monitoring the attached storage for the predetermined threshold time to identify an inaccessible device, wherein the monitoring includes at least starting a timer and using a subroutine if the multi-path host system uses the SDD and performing a predetermined number of retries to attempt to contact the inaccessible device; upon expiration of the predetermined threshold time, issuing the statesave command from a device driver of the multi-path host system through a fabric to one of a plurality of ports on the attached storage; executing the statesave command and collecting state data if the statesave command is received; providing a confirmation that the state save command was received and executed; and upon a successful execution of the state save command, creating an entry in a log file of the device driver for documenting the successful execution of the state save command.