System for assignment of work requests by identifying servers in a multisystem complex having a minimum predefined capacity utilization at lowest importance level

• US 5,881,238 A
• Filed: 02/10/1997
• Issued: 03/09/1999
• Est. Priority Date: 06/07/1995
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Dillenberger, Donna Ngar Ting, Cotner, Curt Lee, Aman, Jeffrey David, Emmes, David Bruce
• Primary Examiner(s): Lee, Thomas C.
• Assistant Examiner(s): Chen, Anderson I.
• Application Number:
  US08/797,899
• Time in Patent Office: 757 Days
• Field of Search: 364/229, 364/284.4, 364/281.7, 395/200.56, 395/674, 395/500, 395/680
• US Class Current: 709/226
• CPC Class Codes: G06F 2209/5022 Workload threshold
• CPC Class Codes: G06F 9/505 considering the load
• CPC Class Codes: G06F 9/5083 Techniques for rebalancing the load in a distributed system

Abstract

Apparatus and accompanying methods for use preferably in a multi-system shared data (sysplex) environment (100), wherein each system (110) provides one or more servers (115), for dynamically and adaptively assigning and balancing new work and for new session requests, among the servers in the sysplex, in view of attendant user-defined business importance of these requests and available sysplex resource capacity so as to meet overall business goals. Specifically, systems and servers are categorized into two classes: eligible, i.e., goal-oriented servers running under a policy and for which capacity information is currently available, and candidate, i.e., servers which lack capacity information. Work requests for a client application are assigned first to various eligible systems and eligible servers thereon based on their current capacity to accept new work and in a manner that meets business goals inherent in a sysplex policy; followed, if additional servers are requested by that application, to candidate systems and candidate servers thereon. As to session placement, first those system(s) are selected that have lowest utilization, at a target importance level, but with sufficient available capacity at that level. Competing servers on the selected system(s) are then evaluated based on their corresponding session count data to yield a single resulting server. Thereafter, identification of multiple servers and their corresponding weights are returned to, e.g., a client application, for eventual routing of work requests to those servers, or the identification of a single server is returned to that application for establishing a new session therewith.

Claims

1. In a multisystem complex comprising a plurality of computer systems, each of which has one or more servers residing thereon and has an ascertainable capacity utilization at each of a plurality of importance levels that are commonly defined across said complex with work at a higher importance level having priority over work at a lower importance level, a method of assigning one or more work requests among said servers in response to an incoming request to route work, comprising the steps of:

identifying one or more eligible systems in said complex having at least a minimum predefined capacity utilization at a lowest importance level across said sysplex; and

identifying one or more servers residing on said one or more eligible systems for assignment of said work requests thereto.

2. The method of claim 1 in which said incoming request originates from a client application, said method further comprising the step of:

transmitting a list identifying said one or more servers to said client application.

3. The method of claim 2 in which said client application performs the further step of:

routing said one or more work requests to servers identified in said list.

4. The method of claim 1, further comprising the steps of:

assigning a set of weights to said one or more servers residing on said one or more eligible systems.

5. The method of claim 4 wherein said work requests are assigned to said servers on said eligible systems in accordance with the weights assigned thereto.

6. The method of claim 4 wherein said work requests are assigned to said servers on said eligible systems in proportion to the weights assigned thereto.

7. The method of claim 4 wherein said step of assigning weights to said one or more servers comprises the steps of:

assigning a weight to each eligible system representing the capacity utilization of the system at said lowest importance level; and

assigning a weight to each server residing on an eligible system in accordance with the weight assigned to the system and the number of servers on that system.

8. A program storage device readable by a machine, tangibly embodying a program of instructions executable by the machine to perform the method steps of claim 1.

9. In a multisystem complex comprising a plurality of computer systems, each of which has one or more servers residing thereon and at least some of which have available capacity utilization data, a method of assigning one or more work requests among said servers in response to an incoming request to route work, comprising the steps of:

identifying one or more eligible systems in said complex on the basis of said available capacity utilization data for assignment of said work requests;

identifying one or more candidate systems in said complex for assignment of said work requests;

identifying one or more servers residing on said one or more eligible systems for assignment at least a subset of said work requests thereto; and

identifying one or more servers residing on said one or more candidate systems for assignment of any remaining work requests thereto if additional servers are required.

10. The method of claim 9 in which said incoming request originates from a client application, said method further comprising the step of:

transmitting a list identifying said servers residing on said eligible and candidate systems to said client application.

11. The method of claim 10 in which said client application performs the further step of:

routing said one or more work requests to servers identified in said list.

12. The method of claim 9 in which said work requests are preferentially assigned to said one or more servers residing on said one or more eligible systems.

13. The method of claim 9 wherein said one or more candidate systems comprise systems lacking available capacity utilization data.

14. The method of claim 9, further comprising the steps of:

assigning a first set of weights to said one or more servers residing on said one or more eligible systems; and

assigning a second set of weights to said one or more servers residing on said one or more candidate systems.

15. The method of claim 14 wherein said work requests are assigned to said servers on said eligible and candidate systems in proportion to the weights assigned thereto.

16. The method of claim 14 wherein said weights are so selected as to favor assignment of said work requests to said one or more servers residing on said one or more eligible systems.

17. The method of claim 14 wherein said servers on said eligible and candidate systems are assigned equal weights if more than a predetermined portion of said servers reside on said candidate systems.

18. A program storage device readable by a machine, tangibly embodying a program of instructions executable by the machine to perform the method steps of claim 9.

19. In a multisystem complex comprising a plurality of computer systems, each of which has one or more servers residing thereon and has an ascertainable capacity utilization at each of a plurality of importance levels that are commonly defined across said complex with work at a higher importance level having priority over work at a lower importance level, apparatus for assigning one or more work requests among said servers in response to an incoming request to route work, comprising:

means for identifying one or more eligible systems in said complex having at least a minimum predefined capacity utilization at a lowest importance level across said sysplex; and

means for identifying one or more servers residing on said one or more eligible systems for assignment of said work requests thereto.

20. The apparatus of claim 19 in which said incoming request originates from a client application, said apparatus further comprising:

means for transmitting a list identifying said one or more servers to said client application.

21. The apparatus of claim 19, further comprising:

means for assigning a set of weights to said one or more servers residing on said one or more eligible systems.

22. The apparatus of claim 21 wherein said means for assigning weights to said one or more servers comprises:

means for assigning a weight to each eligible system representing the capacity utilization of the system at said lowest importance level; and

means for assigning a weight to each server residing on an eligible system in accordance with the weight assigned to the system and the number of servers on that system.

23. In a multisystem complex comprising a plurality of computer systems, each of which has one or more servers residing thereon and at least some of which have available capacity utilization data, apparatus for assigning one or more work requests among said servers in response to an incoming request to route work, comprising:

means for identifying one or more eligible systems in said complex on the basis of said available capacity utilization data for assignment of said work requests;

means for identifying one or more candidate systems in said complex for assignment of said work requests;

means for identifying one or more servers residing on said one or more eligible systems for assignment at least a subset of said work requests thereto; and

means for identifying one or more servers residing on said one or more candidate systems for assignment of any remaining work requests thereto if additional servers are required.

24. The apparatus of claim 23 in which said incoming request originates from a client application, said apparatus further comprising:

means for transmitting a list identifying said servers residing on said eligible and candidate systems to said client application.

25. The apparatus of claim 23, further comprising:

means for assigning a first set of weights to said one or more servers residing on said one or more eligible systems; and

means for assigning a second set of weights to said one or more servers residing on said one or more candidate systems.