Path selection methods for storage based remote copy

• US 20020143999A1
• Filed: 03/30/2001
• Published: 10/03/2002
• Est. Priority Date: 03/30/2001
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Yamagami, Kenji
• Granted Patent: US 7,096,269 B2
• Time in Patent Office: Days
• US Class Current: 709/249
• CPC Class Codes: G06F 11/1461 Backup scheduling policy
• CPC Class Codes: G06F 11/1464 for networked environments
• CPC Class Codes: G06F 11/2007 using redundant communication media
• CPC Class Codes: G06F 11/2012 and using different communication protocols
• CPC Class Codes: G06F 11/2074 Asynchronous techniques
• CPC Class Codes: G06F 11/3485 for I/O devices
• CPC Class Codes: G06F 11/349 for interfaces, buses
• CPC Class Codes: G06F 3/0605 by facilitating the interaction with a user or administrator
• CPC Class Codes: G06F 3/0613 in relation to throughput
• CPC Class Codes: G06F 3/0619 in relation to data integrity, e.g. data losses, bit errors
• CPC Class Codes: G06F 3/0635 by changing the path, e.g. traffic rerouting, path reconfiguration
• CPC Class Codes: G06F 3/065 Replication mechanisms
• CPC Class Codes: G06F 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]
• CPC Class Codes: Y10S 707/99952 Coherency, e.g. same view to multiple users
• CPC Class Codes: Y10S 707/99953 Recoverability

Abstract

The present invention provides techniques for managing data flow over a plurality of connections between primary and remote storage devices. In a representative example embodiment, when the primary storage system copies data to the secondary storage system, it chooses one of a plurality of networks connecting it to the secondary storage system, depending upon a users'"'"' policy. Since networks have different characteristics, in terms of, for example, performance, security, reliability, and costs, the user can specify which network(s) are used under various circumstances, i.e., daytime operation, nighttime operation, normal operation, emergency, and so forth. The storage systems comprise a mapping of volumes and ports. When performing copy operations, the primary storage system finds a volume storing the data, and available ports by accessing the mapping. The mappings are based upon policies that are input by a user.

Claims

1. A storage system apparatus, comprising:

at least one of a plurality of disk drives;

a memory, operable to contain path selection information;

a plurality of ports, providing switch-able connection to a plurality of networks; and

a processor;

wherein said plurality of networks each has at least one of a plurality of user provided policies associated therewith, and wherein said processor, based upon monitoring of at least one of a plurality of conditions in said plurality of networks, selects at least one of said plurality of ports connecting said plurality of networks, based upon a comparison of said at least one of a plurality of conditions in said plurality of networks to a plurality of user provided policies.

2. The storage system apparatus of claim 1, wherein said at least one of a plurality of conditions comprises at least one of a throughput, a busy rate, an error rate, and a presence of an error.

3. The storage system apparatus of claim 1, further comprising a plurality of status indications, said plurality of networks each having at least one of said plurality of status indications associated therewith;

and wherein said processor determines based upon said status indication whether to select a port from said at least one of a plurality of ports connecting said plurality of networks.

4. The storage system apparatus of claim 3, further comprising a network monitor, said network monitor operable to detect a condition within at least one of said plurality of networks, and thereupon set said value in said status indication.

5. The storage system apparatus of claim 3, wherein said status indication comprises at least one of available, temporarily unavailable, and unavailable.

6. The storage system apparatus of claim 1, wherein said policy comprises at least one of a threshold, a maximum, a minimum, an average, a mean, a limit, a constraint, a priority, and a target.

7. The storage system apparatus of claim 1, wherein said plurality of networks are grouped into a plurality of path groups, wherein said policies are associated with networks in a particular path group.

8. The storage system apparatus of claim 7, wherein said at least one of a plurality of disk drives comprises at least one of a plurality of volumes.

9. The storage system apparatus of claim 8, wherein each of said at least one of a plurality of volumes is permitted to access networks of at least one of said plurality of path groups.

10. A method for minimizing cost of network access by a storage apparatus, said method comprising:

specifying a first network to be used for transferring data;

specifying a constraint for said first network;

specifying a second network to be used for transferring data;

transferring data using said first network when conditions in said first network are in accordance with said constraint, otherwise transferring data using said second network.

11. The method of claim 10, further comprising:

transferring a portion of said data using said first network even when conditions in said first network are not in accordance with said constraint as a test;

monitoring conditions in said first network during said test; and

returning to transferring data using said first network when said test reveals that conditions in said first network are again in accordance with said constraint.

12. The method of claim 10, wherein said first network is relatively less expensive to use than said second network.

13. The method of claim 10, wherein specifying said constraint for said first network comprises specifying at least one of a throughput, a busy rate, an error rate, and a presence of an error.

14. The method of claim 10, wherein said first network is a public network and said second network is a private network.

15. The method of claim 10, further comprising:

making said first network a higher priority network than said second network.

16. The method of claim 10, further comprising:

detecting an abnormal condition in said first network and thereupon transferring data using said second network.

18. The method of claim 17, wherein selecting at least one of a plurality of ports connecting to said plurality of networks comprises:

determining based upon a status indication whether to select a port from said at least one of a plurality of ports connecting said plurality of networks.

19. The method of claim 17, further comprising:

associating said plurality of networks with a plurality of path groups;

wherein said at least one of a plurality of policies is associated with at least one of a plurality of path groups.

20. The method of claim 17, wherein monitoring at least one of a plurality of conditions in a plurality of networks comprises:

using a network monitor to detect a condition within at least one of said plurality of networks, and thereupon set a value in a status indication.

17. A method for selecting a network, said method comprising:

monitoring at least one of a plurality of conditions in a plurality of networks;

comparing said at least one of a plurality of conditions in said plurality of networks to at least one of a plurality of user provided policies; and

selecting at least one of a plurality of ports connecting to said plurality of networks;

wherein said plurality of networks each has at least one of said plurality of user provided policies associated therewith.