Methods and system for reserving storage space for data migration in a redundant hierarchic data storage system by dynamically computing maximum storage space for mirror redundancy

Claim 1

A method for reserving space in a hierarchic data storage system; the data storage system comprising a disk array with a number of storage disks that define a physical storage space of a physical capacity, the physical storage space being mapped into a RAID-level virtual storage space having mirror and parity RAID areas, the RAID-level virtual storage space being mapped into an application-level virtual storage space having multiple virtual blocks which are associated with the mirror and parity RAID areas; the method comprising the following steps: (a) allocating virtual blocks in the application-level virtual storage space in mirror RAID areas for storing data according to mirror redundancy; (b) storing data in the virtual blocks; (c) determining an allocated capacity representing a total number of virtual blocks that are presently being used to store data; and (d) dynamically computing a maximum allowable number of virtual blocks in mirror RAID areas as a function of the physical capacity, the allocated capacity, and the number of storage disks in the disk array in response to changes in the allocated capacity.

Claim 2

A method for reserving space in a hierarchic data storage system; the data storage system comprising a disk array with a number of storage disks that define a physical storage space of a physical capacity, the physical storage space being mapped into a RAID-level virtual storage space having mirror and parity RAID areas, the RAID-level virtual storage space being mapped into an application-level virtual storage space having multiple virtual blocks which are associated with the mirror and parity RAID areas; the method comprising the following steps: (a) allocating virtual blocks in the application-level virtual storage space in mirror RAID areas for storing data according to mirror redundancy; (b) storing data in the virtual blocks; (c) determining an allocated capacity representing a total number of virtual blocks that are presently being used to store data; and (d) dynamically computing a maximum allowable number of virtual blocks in mirror RAID areas as a function of the physical capacity, the allocated capacity, and the number of storage disks in the disk array in response to changes in the allocated capacity.

Claim 11

A method for reserving space in a hierarchic data storage system; the data storage system comprising a disk array of multiple storage disks that define a physical storage space; the method comprising the following steps: (a) providing a physical capacity of the physical storage space in the disk array; (b) mapping the physical storage space into a RAID-level virtual storage space having multiple mirror and parity RAID areas; (c) mapping the RAID-level virtual storage space into an application-level virtual storage space having multiple virtual blocks; (d) allocating the virtual blocks in the application-level virtual storage space in mirror RAID areas for storing data according to mirror redundancy; (e) storing data in the virtual blocks; (f) determining an allocated capacity representing a total number of virtual blocks that are presently being used to store data; (g) comparing the allocated capacity to the physical capacity; and (h) if the allocated capacity is greater than or equal to one-half of the physical capacity, conducting the following steps: (1) dynamically computing a maximum allowable number of virtual blocks in mirror RAID areas as a function of the physical capacity and the allocated capacity in response to changes in the allocated capacity; (2) restricting allocation of more virtual blocks in mirror RAID areas than the computed maximum allowable number of virtual blocks in mirror RAID areas; (3) allocating the virtual blocks in the application-level virtual storage space in parity RAID areas for storing data according to parity redundancy; and (4) storing data in virtual blocks in both the mirror and parity RAID areas.

Claim 12

A method for reserving space in a hierarchic data storage system; the data storage system comprising a disk array of multiple storage disks that define a physical storage space; the method comprising the following steps: (a) providing a physical capacity of the physical storage space in the disk array; (b) mapping the physical storage space into a RAID-level virtual storage space having multiple mirror and parity RAID areas; (c) mapping the RAID-level virtual storage space into an application-level virtual storage space having multiple virtual blocks; (d) allocating the virtual blocks in the application-level virtual storage space in mirror RAID areas for storing data according to mirror redundancy; (e) storing data in the virtual blocks; (f) determining an allocated capacity representing a total number of virtual blocks that are presently being used to store data; (g) comparing the allocated capacity to the physical capacity; and (h) if the allocated capacity is greater than or equal to one-half of the physical capacity, conducting the following steps: (1) dynamically computing a maximum allowable number of virtual blocks in mirror RAID areas as a function of the physical capacity and the allocated capacity in response to changes in the allocated capacity; (2) restricting allocation of more virtual blocks in mirror RAID areas than the computed maximum allowable number of virtual blocks in mirror RAID areas; (3) allocating the virtual blocks in the application-level virtual storage space in parity RAID areas for storing data according to parity redundancy; and (4) storing data in virtual blocks in both the mirror and parity RAID areas.

Claim 22

A method for reserving space in a hierarchic data storage system; the data storage system comprising a homogeneous disk array with a number of equal sized storage disks that define a physical storage space of a physical capacity, the physical storage space being mapped into a RAID-level virtual storage space having mirror and parity RAID areas, the RAID-level virtual storage space being mapped into an application-level virtual storage space having multiple virtual blocks which are associated with the mirror and parity RAID areas; the method comprising the following steps: allocating virtual blocks in the application-level virtual storage space in mirror RAID areas for storing data according to mirror redundancy; storing data in the virtual blocks; determining an allocated capacity representing a total number of virtual blocks that are presently being used to store data; and computing a maximum allowable number of virtual blocks in the mirror RAID areas according to the following equation: ##EQU5## where "n" equals the number of storage disks in the disk array, "AllCap" represents the allocated capacity based on the count of the virtual blocks, and "PhyCap" represents the physical capacity of the disk array.

Claim 23

A method for reserving space in a hierarchic data storage system; the data storage system comprising a homogeneous disk array with a number of equal sized storage disks that define a physical storage space of a physical capacity, the physical storage space being mapped into a RAID-level virtual storage space having mirror and parity RAID areas, the RAID-level virtual storage space being mapped into an application-level virtual storage space having multiple virtual blocks which are associated with the mirror and parity RAID areas; the method comprising the following steps: allocating virtual blocks in the application-level virtual storage space in mirror RAID areas for storing data according to mirror redundancy; storing data in the virtual blocks; determining an allocated capacity representing a total number of virtual blocks that are presently being used to store data; and computing a maximum allowable number of virtual blocks in the mirror RAID areas according to the following equation: ##EQU5## where "n" equals the number of storage disks in the disk array, "AllCap" represents the allocated capacity based on the count of the virtual blocks, and "PhyCap" represents the physical capacity of the disk array.

Claim 25

A method for reserving space in a hierarchic data storage system; the data storage system comprising a heterogeneous disk array with a number of various sized storage disks that define a physical storage space of a physical capacity, the physical storage space being mapped into a RAID-level virtual storage space having mirror and parity RAID areas, the RAID-level virtual storage space being mapped into an application-level virtual storage space having multiple virtual blocks which are associated with the mirror and parity RAID areas; the method comprising the following steps: allocating virtual blocks in the application-level virtual storage space in mirror RAID areas for storing data according to mirror redundancy; storing data in the virtual blocks; determining an allocated capacity representing a total number of virtual blocks that are presently being used to store data; and computing a maximum allowable number of virtual blocks in the mirror RAID areas according to the following equation: ##EQU6## where "n" equals the number of storage disks in the disk array, "AllCap" represents the allocated capacity, "PhyCap" represents the physical capacity of the disk array, and "i" is the number of homogenous disk array representations that can be created from the heterogeneous disk array.

Claim 26

A method for reserving space in a hierarchic data storage system; the data storage system comprising a heterogeneous disk array with a number of various sized storage disks that define a physical storage space of a physical capacity, the physical storage space being mapped into a RAID-level virtual storage space having mirror and parity RAID areas, the RAID-level virtual storage space being mapped into an application-level virtual storage space having multiple virtual blocks which are associated with the mirror and parity RAID areas; the method comprising the following steps: allocating virtual blocks in the application-level virtual storage space in mirror RAID areas for storing data according to mirror redundancy; storing data in the virtual blocks; determining an allocated capacity representing a total number of virtual blocks that are presently being used to store data; and computing a maximum allowable number of virtual blocks in the mirror RAID areas according to the following equation: ##EQU6## where "n" equals the number of storage disks in the disk array, "AllCap" represents the allocated capacity, "PhyCap" represents the physical capacity of the disk array, and "i" is the number of homogenous disk array representations that can be created from the heterogeneous disk array.