SYSTEM AND METHOD FOR STORAGE SUBSYSTEM PORT REASSIGNMENT IN STORAGE AREA NETWORKS

• US 20090234984A1
• Filed: 03/13/2008
• Published: 09/17/2009
• Est. Priority Date: 03/13/2008
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Korupolu, Madhukar R., Sarkar, Prasenjit, Chaitanya, Shiva, Gupta, Karan
• Granted Patent: US 7,930,448 B2
• Time in Patent Office: Days
• US Class Current: 710/33
• CPC Class Codes: G06F 13/385 for adaptation of a particular data processing system to different peripheral devices
• CPC Class Codes: G06F 2003/0697 device management, e.g. handlers, drivers, I/O schedulers
• CPC Class Codes: G06F 3/0601 Interfaces specially adapted for storage systems
• CPC Class Codes: G06F 3/0604 Improving or facilitating administration, e.g. storage management
• CPC Class Codes: G06F 3/0635 by changing the path, e.g. traffic rerouting, path reconfiguration
• CPC Class Codes: G06F 3/0653 Monitoring storage devices or systems
• CPC Class Codes: G06F 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]
• CPC Class Codes: H04L 67/1001 for accessing one among a plurality of replicated servers
• CPC Class Codes: H04L 67/1008 based on parameters of servers, e.g. available memory or workload monitoring of computer activity G06F11/30
• CPC Class Codes: H04L 67/1031 Controlling of the operation of servers by a load balancer, e.g. adding or removing servers that serve requests

Abstract

A method and system for data traffic management in a storage area network subsystem connected to multiple hosts via plural ports through a connection network is provided. Traffic management involves, for each port, determining input/output (IO) traffic utilization load of the port based on workloads from one or more hosts assigned to that port; and detecting if a port is in utilization overload. Then, upon detecting a port utilization overload, port traffic is managed by adjusting traffic utilization of the overloaded port and one or more other ports in the storage subsystem, to reduce traffic utilization of the overloaded port.

Claims

1. A method for traffic management in a storage area network subsystem connected to multiple hosts via plural ports through a connection network, comprising the steps of:

for each port, determining input/output (IO) traffic utilization load of the port based on workloads from one or more hosts assigned to that port;

detecting if a port is in utilization overload; and

upon detecting a port utilization overload, managing port traffic by adjusting traffic utilization of the overloaded port and one or more other ports in the storage subsystem using port addition, port deletion and/or port migration, to reduce traffic utilization of the overloaded port.

2. The method of claim 1, wherein the step of detecting port utilization overload includes determining if traffic utilization for a port is above a threshold.

3. The method of claim 2, wherein managing port traffic by port deletion includes:

for a host with an overloaded port, reassigning the traffic between said host and the overloaded port, among one or more other ports that are assigned to said host, without overloading said other assigned ports, wherein said other assigned ports are reachable by said host through the network.

4. The method of claim 2, wherein managing port traffic further includes the steps of:

(a) determining spare traffic capacity of other ports assigned to a host that is assigned to the overloaded port, wherein the spare capacity of a port, SC (port, T), is computed as the amount of traffic that can be pushed through that port without the port utilization exceeding a threshold T; and

(b) reassigning the traffic between said host and the overloaded port, among one or more of said other assigned ports with spare traffic capacity, without overloading said other assigned ports.

5. The method of claim 4, wherein managing port traffic further includes the steps of:

(c) determining if the overloaded port remains overloaded; and

(d) if the overloaded port remains overloaded, then repeating steps (a) through (d).

6. The method of claim 2, wherein managing port traffic by port migration includes:

for a host with an overloaded port, selecting a port reachable by said host through the connection network, the selected port having sufficient spare traffic capacity to accommodate said traffic between the overloaded port and said host, and migrating said traffic from the overloaded port to the selected port.

7. The method of claim 2, wherein managing port traffic further includes the steps of:

(a) determining spare traffic capacity of other ports assigned to a host that is assigned to the overloaded port, wherein the spare capacity of a port, SC (port, T), is computed as the amount of traffic that can be pushed through that port without the port utilization exceeding a threshold T; and

(b) selecting a port among said assigned ports, with sufficient spare traffic capacity to accommodate said traffic between the overloaded port and said host, and migrating said traffic from the overloaded port to the selected port.

8. The method of claim 7, wherein managing port traffic further includes the steps of:

(c) determining if the overloaded port remains overloaded; and

(d) if the overloaded port remains overloaded, then repeating steps (a) through (d).

9. The method of claim 2, wherein managing port traffic by port addition includes:

for a host with an overloaded port, selecting a port reachable by said host through the connection network, the selected port having sufficient spare traffic capacity to accommodate at least a portion of the traffic between the overloaded port and said host, assigning the selected port to the host, and migrating said portion of traffic from the overloaded port to the selected port.

10. The method of claim 2, wherein managing port traffic further includes the steps of:

(a) determining spare traffic capacity of other ports assigned to a host that is assigned to the overloaded port, wherein the spare capacity of a port, SC (port, T), is computed as the amount of traffic that can be pushed through that port without the port utilization exceeding a threshold T; and

(b) selecting a port among said assigned ports, with sufficient spare traffic capacity to accommodate at least a portion of the traffic between the overloaded port and said host, assigning the selected port to the host, and migrating said portion of traffic from the overloaded port to the selected port.

11. The method of claim 10, wherein managing port traffic further includes the steps of:

(c) determining if the overloaded port remains overloaded; and

(d) if the overloaded port remains overloaded, then repeating steps (a) through (d).

12. The method of claim 1, wherein the storage subsystem comprises a storage area network.

13. An apparatus for traffic management in a storage subsystem connected to multiple hosts via plural ports through a connection network, comprising:

a monitor configured for determining input/output (IO) traffic utilization load of the port based on workloads from one or more hosts assigned to that port; and

a controller configured for detecting if a port is in utilization overload, and upon detecting a port utilization overload, managing port traffic by adjusting traffic utilization of the overloaded port and one or more other ports in the storage subsystem using port addition, port deletion and/or port migration, to reduce traffic utilization of the overloaded port.

14. The apparatus of claim 13, wherein the controller is configured for detecting port utilization overload by determining if traffic utilization for a port is above a threshold.

15. The apparatus of claim 14, wherein the controller is configured for port deletion by:

for a host with an overloaded port, reassigning the traffic between said host and the overloaded port, among one or more other ports that are assigned to said host, without overloading said other assigned ports, wherein said other assigned ports are reachable by said host through the network.

16. The apparatus of claim 14, wherein the controller is configured for managing port traffic by:

(a) determining spare traffic capacity of other ports assigned to a host that is assigned to the overloaded port, wherein the spare capacity of a port, SC (port, T), is computed as the amount of traffic that can be pushed through that port without the port utilization exceeding a threshold T;

(b) reassigning the traffic between said host and the overloaded port, among one or more of said other assigned ports with spare traffic capacity, without overloading said other assigned ports;

(c) determining if the overloaded port remains overloaded; and

(d) if the overloaded port remains overloaded, then repeating steps (a) through (d).

17. The apparatus of claim 14, wherein the controller is configured for port migration by:

for a host with an overloaded port, selecting a port reachable by said host through the connection network, the selected port having sufficient spare traffic capacity to accommodate said traffic between the overloaded port and said host, and migrating said traffic from the overloaded port to the selected port.

18. The apparatus of claim 14, wherein the controller is configured for managing port traffic by:

(a) determining spare traffic capacity of other ports assigned to a host that is assigned to the overloaded port, wherein the spare capacity of a port, SC (port, T), is computed as the amount of traffic that can be pushed through that port without the port utilization exceeding a threshold T;

(b) selecting a port among said assigned ports, with sufficient spare traffic capacity to accommodate said traffic between the overloaded port and said host, and migrating said traffic from the overloaded port to the selected port;

(c) determining if the overloaded port remains overloaded; and

(d) if the overloaded port remains overloaded, then repeating steps (a) through (d).

19. The apparatus of claim 14, wherein the controller is configured for port addition by:

for a host with an overloaded port, selecting a port reachable by said host through the connection network, the selected port having sufficient spare traffic capacity to accommodate at least a portion of the traffic between the overloaded port and said host, assigning the selected port to the host, and migrating said portion of traffic from the overloaded port to the selected port.

20. The apparatus of claim 14 wherein the controller is configured for managing port traffic by:

(a) determining spare traffic capacity of other ports assigned to a host that is assigned to the overloaded port, wherein the spare capacity of a port, SC (port, T), is computed as the amount of traffic that can be pushed through that port without the port utilization exceeding a threshold T;

(b) selecting a port among said assigned ports, with sufficient spare traffic capacity to accommodate at least a portion of the traffic between the overloaded port and said host, assigning the selected port to the host, and migrating said portion of traffic from the overloaded port to the selected port;

(c) determining if the overloaded port remains overloaded; and

(d) if the overloaded port remains overloaded, then repeating steps (a) through (d).

21. The apparatus of claim 13, wherein the storage subsystem comprises a storage area network.

22. A computing system comprising:

a storage subsystem connected to multiple hosts via plural ports through a connection network;

a port management module for port traffic management, comprising;

a monitor configured for determining input/output (IO) traffic utilization load of the port based on workloads from one or more hosts assigned to that port; and

a controller configured for detecting if a port is in utilization overload, and upon detecting a port utilization overload, managing port traffic by adjusting traffic utilization of the overloaded port and one or more other ports in the storage subsystem using port addition, port deletion and/or port migration, to reduce traffic utilization of the overloaded port.

23. The system of claim 22, wherein the controller is configured for port deletion by:

(a) determining spare traffic capacity of other ports assigned to a host that is assigned to the overloaded port, wherein the spare capacity of a port, SC (port, T), is computed as the amount of traffic that can be pushed through that port without the port utilization exceeding a threshold T;

(b) reassigning the traffic between said host and the overloaded port, among one or more of said other assigned ports with spare traffic capacity, without overloading said other assigned ports;

(c) determining if the overloaded port remains overloaded; and

(d) if the overloaded port remains overloaded, then repeating steps (a) through (d).

24. The system of claim 22, wherein the controller is configured for port migration by:

(a) determining spare traffic capacity of other ports assigned to a host that is assigned to the overloaded port, wherein the spare capacity of a port, SC (port, T), is computed as the amount of traffic that can be pushed through that port without the port utilization exceeding a threshold T;

(b) selecting a port among said assigned ports, with sufficient spare traffic capacity to accommodate said traffic between the overloaded port and said host, and migrating said traffic from the overloaded port to the selected port;

(c) determining if the overloaded port remains overloaded; and

(d) if the overloaded port remains overloaded, then repeating steps (a) through (d).

25. The system of claim 22, wherein the controller is configured for port addition by:

(a) determining spare traffic capacity of other ports assigned to a host that is assigned to the overloaded port, wherein the spare capacity of a port, SC (port, T), is computed as the amount of traffic that can be pushed through that port without the port utilization exceeding a threshold T;

(b) selecting a port among said assigned ports, with sufficient spare traffic capacity to accommodate at least a portion of the traffic between the overloaded port and said host, assigning the selected port to the host, and migrating said portion of traffic from the overloaded port to the selected port;

(c) determining if the overloaded port remains overloaded; and

(d) if the overloaded port remains overloaded, then repeating steps (a) through (d).