Method for maximizing sequential output in a disk array storage device
AssigneeEMC Corporation
InventorEitan Bachmat
Life of this patent
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Abstract
Load balancing of activities on physical disk storage devices is accomplished by monitoring reading and writing operations to blocks of contiguous storage locations on the physical disk storage devices. A list of exchangeable pairs of blocks is developed based on size and function. Statistics accumulated over an interval are then used to obtain access activity values for each block and each physical disk drive. A statistical analysis leads to a selection of one block pair. After testing to determine any adverse effect of making that change, the exchange is made to more evenly distribute the loading on individual physical disk storage devices.
Claims27
A method for balancing activity on a plurality of physical disk storage devices wherein at least two of the physical disk storage devices are divided into a plurality of blocks of contiguous storage locations for storing data, said method comprising the steps of:
- A) compiling disk utilization statistics for each block in each physical disk storage device over a time interval,
- B) compiling a list of all pairs of exchangeable blocks wherein each block in a pair is located on different ones of the physical disk storage devices,
- C) selecting a configuration of blocks on physical disk storage devices with exchanged blocks based upon the compiled disk utilization statistics, and
- D) exchanging the data in the selected pair of exchangeable blocks.
A method for balancing activity on a plurality of physical disk storage devices wherein at least two of the physical disk storage devices are divided into a plurality of logical volumes, said method comprising the steps of:
- A) compiling a list of all pairs of exchangeable logical volumes on the physical disk storage devices,
- B) defining an analysis time interval comprising a plurality of subintervals;
- C) recording as a function of time in each subinterval, disk accesses for each logical volume over the entire analysis time interval,
- D) converting the disk accesses for each logical volume into time-based disk utilization statistics for each logical volume and each physical disk storage device for the analysis time interval,
- E) selecting a pair of logical volumes on different physical disk storage devices for an exchange based upon the time-based disk utilization statistics, and
- F) exchanging the pair of logical volumes if it is determined that the exchange of the selected pair of logical volumes will improve the operation of the physical disk storage devices.
A method for balancing activity on a plurality of physical disk storage devices divided into a plurality of logical volumes, said method comprising the steps of:
- A) compiling a list of all pairs of exchangeable logical volumes on the physical disk storage devices wherein an exchangeable pair includes logical volumes on different physical disk storage devices,
- B) defining an analysis time interval,
- C) recording disk accesses for each logical volume over the analysis time interval,
- D) converting the disk accesses for each logical volume into time-based disk utilization statistics for each logical volume for the analysis time interval,
- E) selecting a pair of logical volumes on different physical disk storage devices for an exchange based upon the time-based disk utilization statistics, and
- F) exchanging the data in the pair of logical volumes if it is determined that the exchange of the selected pair of logical volumes will improve the operation of the physical disk storage devices.
Dependencies are inferred from the claim text.