Open host issued statesave to attached storage

• US 8,806,081 B2
• Filed: 02/19/2008
• Issued: 08/12/2014
• Est. Priority Date: 02/19/2008
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Fleming, Mark Sean, Martinez, Lisa R.
• Primary Examiner(s): Tsai, Henry
• Assistant Examiner(s): ROCHE, JOHN B
• Application Number:
  US12/033,606
• Publication Number:
  US 20090210574A1
• Time in Patent Office: 2,366 Days
• Field of Search: 710/19
• US Class Current: 710/19
• CPC Class Codes: G06F 11/0757 by exceeding a time limit, i.e. time-out, e.g. watchdogs
• CPC Class Codes: G06F 11/0778 Dumping, i.e. gathering error/state information after a fault for later diagnosis
• CPC Class Codes: G06F 11/201 between storage system components

Abstract

A method to issue a statesave command from a host system to attached storage is provided. The attached storage is monitored for a predetermined threshold time to identify an inaccessible device. Upon expiration of the predetermined threshold time, the statesave command is issued from a device driver of the host system to the attached storage.

Claims

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.

2. The method of claim 1, further including, upon a failure of the statesave command, creating an entry in a log file of the device driver.

3. The method of claim 1, wherein monitoring the attached storage includes executing the predetermined number of retries to the inaccessible device using the device driver for the predetermined threshold time.

10. The method of claim 1, further including, in association with the monitoring, performing:

performing a load balancing operation for Input/Output (I/O) commands across the multipath host system.

11. The method of claim 1, further including, subsequent to the issuing, executing the statesave command by the attached storage and collecting the state data.

16. The method of claim 1, wherein monitoring further includes:

identifying an inaccessible volume that starts a timer, and attempting to contact the inaccessible volume for a predetermined number of retries.

4. A multi-path host system to issue a statesave command from the multi-path host system to attached storage, comprising:

the multi-path system;

the attached storage in communication with the multi-path system;

an application operational on the multi-path host system and in communication with the attached storage;

a host operational on the multi-path host system and in communication with the attached storage; and

a device driver responsive to the application and host,

a subsystem device driver (SDD) operational in the multi-path host system;

at least one processor device in communication with the device driver and the multi-path host system, wherein the at least one processor device;

dynamically switches 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,

determines a tolerance time for the host and the 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,

anticipates which application or host is relevant for a particular situation for determining the tolerance time,

sets the timeout parameter using the 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 the 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,

monitors 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, and

executes the statesave command and collecting state data if the statesave command is received,

provides a confirmation that the state save command was received and executed,

upon expiration of the predetermined threshold time, issue a statesave command from the device driver of the multi-path host system through a fabric to one of a plurality of ports on the attached storage, and

upon a successful execution of the state save command, create an entry in a log file of the device driver for documenting the successful execution of the state save command.

5. The system of claim 4, wherein the device driver is further configured to, upon a failure of the statesave command, create an entry in a log file.

6. The system of claim 4, wherein the device driver is further configured to execute the predetermined number of retries to the inaccessible device using the device driver for the predetermined threshold time.

12. The system of claim 4, wherein the device driver is further configured to, in association with the monitoring:

execute a load balancing operation for Input/Output (I/O) commands across the multipath host system.

13. The system of claim 4, wherein the device driver is further configured to execute the issued statesave command by the attached storage and collect the state data.

17. The system of claim 4, wherein the device driver is further configured to, in association with the monitoring:

identify an inaccessible volume that starts a timer, and attempt to contact the inaccessible volume for a predetermined number of retries.

7. A computer program product for issuing a statesave command from a multi-path host system to attached storage, the computer program product comprising a non-transitory computer-readable storage medium having computer-readable program code portions stored therein, the computer-readable program code portions comprising:

a first executable portion for 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

a second executable portion for 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;

a third executable portion for setting the timeout parameter using the 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;

a fourth executable portion for 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;

a fifth executable portion for, 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;

a sixth executable portion for executing the statesave command and collecting state data if the statesave command is received;

a seventh executable portion for providing a confirmation that the statesave command was received and executed;

and

an eighth executable portion for, 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.

8. The computer program product of claim 7, further including a ninth executable portion for, upon a failure of the statesave command, creating an entry in a log file of the device driver.

9. The computer program product of claim 7, further including a ninth executable portion for executing a the predetermined number of retries to the inaccessible device using the device driver for the predetermined threshold time.

14. The computer program product of claim 7, further including a ninth executable portion for:

executing a load balancing operation for Input/Output (I/O) commands across the multipath host system.

15. The computer program product of claim 7, further including a ninth executable portion for, subsequent to the issuing, executing the statesave command by the attached storage and collecting the state data.

18. The computer program product of claim 7, further including a ninth executable portion for:

identifying an inaccessible volume that starts the timer, and attempting to contact the inaccessible volume for a predetermined number of retries.