Information processing system and method of allocating I/O to paths in same

• US 7,873,759 B2
• Filed: 12/23/2008
• Issued: 01/18/2011
• Est. Priority Date: 10/30/2008
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Kobayashi, Nobuo, Yokouchi, Hiroshi, Tomonaga, Shigenori
• Primary Examiner(s): Tseng; Cheng-Yuan
• Application Number:
  US12/342,314
• Publication Number:
  US 20100115154A1
• Time in Patent Office: 756 Days
• Field of Search: None
• US Class Current: 710/38
• CPC Class Codes: G06F 13/4022 using switching circuits, e.g. switching matrix, connection or expansion network G06F13/4009 takes precedence

Abstract

Provided is an information processing system that communicates with a storage apparatus through a plurality of paths P_i (i=1 to n, where n is a total number of the paths), and that issues an I/O to the storage apparatus through one of the paths P_i. The information processing system sets weights W_i for the respective paths P_i; obtains an I/O issue interval d_i of each of the paths P_i by dividing a sum total ΣW_i of the weights W_i by the weight W_i set for the path P_i; obtains I/O issue timings t_i(m)of each of the paths P_i by using the following equation: t_i(m)=d_i/C+m·d_i (m=0, 1, 2, . . . ) (where C is a constant); and issues the I/Os to the paths P_i in an order corresponding to the an order of the I/O issue timings t_i(m) chronologically arranged.

Claims

1. An information processing system that communicates with a storage apparatus through a plurality of paths P_i (i=1 to n, where n is a total number of the paths), and issues an I/o to the storage apparatus through one of the paths P_i, the information processing system comprising:

a first processing unit that sets weights W_i to the respective paths P_i;

a second processing unit that obtains an I/O issue interval d_i by dividing a sum total Σ

W_i of the weights W_i by the weight W_i set to the respective paths P_i;

a third processing unit that obtains I/O issue timings t_i(m)of each of the paths P_i from the following equation;

t_i(m)=d_i/C+m·

d_i (m=0, 1, 2, . . . ) (where C is a constant);

and

a fourth processing unit that issues the I/Os to the paths P_i in an order corresponding to an order of the I/O issue timings t_i(m) chronologically arranged.

2. The information processing system according to claim 1, wherein

the first processing unit recalculates the weights W_i when load change in the path P_i has exceeded a threshold value,

the second processing unit obtains again the I/O issue interval d_i, based on the weights W_i thus recalculated,

the third processing unit obtains again the I/O issue timings t_i(m), based on the once again obtained I/O issue interval d_i, and

the fourth processing unit issues the I/Os to the paths P_i in an order corresponding to an order of the once again obtained I/O issue timings t_i(m) chronologically arranged.

3. The information processing system according to claim 1, wherein

the first processing unit sets the weights W_i according to loads on and performance of the respective paths P_i.

4. The information processing system according to claim 1, wherein

the paths P_i are identified by a combination of a network port of the information processing system, a network port of the storage apparatus, and a network port of a switch interposed between the network ports of the information processing system and the storage apparatus.

5. The information processing system according to claim 1, wherein

the fourth processing unit issues the I/Os in an order giving priority to the path P_i having a lower load among the paths P_i having coinciding I/O issue timings t_i(m), when there are paths P_i that have coinciding I/O issue timings t_i(m), the coinciding I/O issue timings t_i(m) being the I/o issue timings t_i(m) of different ones of the paths P_i that coincide with each other as a result of arranging the I/O issue timings t_i(m) in chronological order.

6. The information processing system according to claim 1, wherein

the fourth processing unit issues the I/Os in an order giving priority to the path P_i having a higher performance among the paths P_i having coinciding I/O issue timings t_i(m), when there are paths P_i that have coinciding I/O issue timings t_i(m), the coinciding I/O issue timings t_i(m) being the I/O issue timings t_i(m) of different ones of the paths P_i that coincide with each other as a result of arranging the I/O issue timings t_i(m) in chronological order.

7. The information processing system according to claim 1, wherein

the fourth processing unit cyclically replaces the path P_i given priority to issue the I/Os among the paths P_i each time an I/O issue timing t_i(m) coincides, when having cyclically coinciding I/O issue timings t_i(m), the cyclically coinciding I/O issue timings t_i(m) being the I/O issue timings t_i(m) of different ones of the paths P_i that coincide with each other as a result of arranging the I/O issue timings t_i(m) in chronological order.

8. In an information processing system that communicates with a storage apparatus through the plurality of paths P_i, and issues the I/O to the storage apparatus through one of the paths P_i, a method of allocating an I/O to a plurality of paths P_i (i=1 to n, where n is a total number of the paths) comprising:

a first step of setting weights W_i to the respective paths P_i;

a second step of obtaining an I/O issue interval d_i by dividing a sum total Σ

W_i of the weights W_i by the weight W_i set to the respective paths P_i;

a third step of obtaining I/O issue timings t_i(m) of the respective paths P_i from the following equation;

t_i(m)d_i/C+m·

d_i (m=0, 1, 2, . . . ) (where C is a constant);

and

a fourth step of issuing the I/Os to the paths P_i in an order corresponding to an order of the I/O issue timings t_i(m) chronologically arranged.

9. The method of allocating an I/O to paths in an information processing system according to claim 8, wherein

the information processing system

recalculates the weights W_i, by performing the first step again, when load change in the path P_i has exceeded a threshold value;

obtains again the I/O issue interval d_i based on the recalculated weights W_i by performing the second step;

obtains again the I/O issue timings t_i(m) based on the once again obtained I/O issue interval d_i by performing the third step; and

issues the I/Os to the paths P_i in an order corresponding to an order of the once again obtained I/O issue timings t_i(m) chronologically arranged, by performing the fourth step.