Claims
- 1. A method for determining a total seek time required to access a physical disk storage device that stores data in a plurality of data blocks, said method comprising the steps of:A) collecting the number of disk accesses to each data block during a sample interval, B) generating a first sum of the accesses to all the data blocks, C) generating a second sum that is the sum of all the first sums, D) generating a third sum that is a sum of the squares of all the first sums, and E) combining the first, second and third sums to obtain the total interval required for all the disk accesses to all the data blocks in the physical disk storage device.
- 2. A method as recited in claim 1 wherein the physical disk storage device contains N data blocks and Ai represents the accesses to a given data block, i, said generation of the first sum producing the values:A′i=A1+A2+ . . . +Ai andA′N=A1+A2+ . . . +AN.
- 3. A method as recited in claim 2 wherein said generation of the second sum produces the value: ∑i=1NAi′.
- 4. A method as recited in claim 3 wherein the said generation of the third sum produces the value: ∑i=1NAi′2.
- 5. A method as recited in claim 4 wherein said step of combining the first, second and third sums produces a result according to: ∑i=1NAi′ ∑i=1NAi′2AN′.
- 6. A method as recited in claim 5 wherein accesses to each data block are grouped into different types, said method additionally comprising the step of weighting the numbers of accesses by type whereby the weighted accesses are used for said generation of the first, second and third sums.
- 7. A method as recited in claim 5 wherein accesses to each data block are grouped into read miss, disk write and sequential read types, said method additionally comprising the step of weighting the numbers of accesses according to: WeightedAccesses=Nrm+Nwr2+Nsr4where Nrm, Nwr and Nsr represent the number of accesses of the read miss, write and sequential read types respectively.
- 8. A method as recited in claim 7 wherein said generation of said first, second and third sums is accomplished during N iterations.
- 9. A method as recited in claim 8 wherein partial sums for each of said first, second and third sums are obtained during each iteration.
- 10. A method as recited in claim 9 wherein said combining of the first, second and third sums occurs after the completion of the N iterations.
- 11. A method for determining a total seek time required to access a physical disk storage device that stores data in a plurality of logical volumes, said method comprising the steps of:A) collecting the number of disk accesses to each logical volume during a sample interval, B) weighting the number of disk accesses to each logical volume by grouping the data accesses into read miss, disk write and sequential read types of accesses and generating a weighted accesses value according to: WeightedAccesses=Nrm+Nwr2+Nsr4 where Nrm, Nwr and Nsr represent the number of accesses of the read miss, write and sequential read types respectively. C) generating a first sum of the weighted accesses to all the logical volumes, D) generating a second sum that is the sum of all the first sums, E) generating a third sum that is a sum of the squares of all the first sums, and F) combining the first, second and third sums to obtain the total interval required for all the disk accesses to all the logical volumes in the physical disk storage device.
- 12. A method as recited in claim 11 wherein the physical disk storage device contains N logical volumes and Ai represents the accesses to a given logical volume, i, and wherein said generation of said first, second and third sums includes the steps of:i) producing, for the first sum, the values: A′i=A1+A2+ . . . +Ai, andA′N=A1+A2+ . . . +AN ii) producing for the second sum the value: ∑i=1NAi′iii) producing for the third sum the value: ∑i=1NAi′2wherein said step of combining the first, second and third sums produces a result according to: ∑i=1NAi′ ∑i=1NAi′2AN′.
- 13. A method as recited in claim 12 wherein said generation of said first, second and third sums is accomplished during N iterations.
CROSS REFERENCES TO RELATED APPLICATIONS
This is a continuation-in-part of U.S. Pat. No. 6,189,071 filed Feb. 13, 2001 (Ser. No. 09/143,683 filed Aug. 28, 1998) that is a continuation-in-part of copending application for U.S. Pat. No. 6,088,766 granted Jul. 11, 2000 (Ser. No. 09/002,428 filed Jan. 2, 1998) that is a continuation-in-part of copending application for U.S. Pat. No. 6,061,761 granted May 9, 2000 (Ser. No. 08/944,606 filed Oct. 6, 1997) and that are all assigned to the same assignee as this invention.
U.S. Letters Patent Application Ser. No. 09/396,146 filed on even data herewith for a Mailbox for Controlling Storage Subsystem Reconfigurations and U.S. Letters Patent Application Ser. No. 09/382,752 filed on even date herewith for a Dynamic Mirror Service Policy with Seek Adjustment in a Non-Physical Mirrored Storage Environment, both assigned to the assignee of this invention are incorporated herewith by reference.
U.S. patent application Ser. No. 09/396,218 filed Sep. 15, 1999 for a Method For Transparent Exchange of Logical Volumes in a Disk Array Storage Device filed on even data herewith and assigned to the assignee of this invention.
US Referenced Citations (7)
Continuation in Parts (3)
|
Number |
Date |
Country |
Parent |
09/143683 |
Aug 1998 |
US |
Child |
09/396217 |
|
US |
Parent |
09/002428 |
Jan 1998 |
US |
Child |
09/143683 |
|
US |
Parent |
08/944606 |
Oct 1997 |
US |
Child |
09/002428 |
|
US |