Disk cache control method, disk array system, and storage system
AssigneeHitachi, Ltd.
InventorsYoshifumi Takamoto, Kiyohiro Obara
Life of this patent
Estimating the term…
Abstract
A disk cache controlling method and a disk array system which includes a plurality of disk devices and a disk cache. Data is divided and stored into the disk devices and a plurality of volumes are assigned to the disk devices. A disk array controller controls the disk devices. Assignment of new disk cache areas includes dividing each of the volumes into areas with an arbitrary fixed length, determining an access frequency for each of the divided areas of each of the volumes; and changing assignment of the disk cache areas to the divided areas according to an access frequency for each divided area. The disk cache areas are assigned to the divided areas according to a divided area having an access frequency which is the lowest.
Claims37
A disk cache controlling method in a disk array system including a plurality of disk devices and a disk cache, data being divided and stored into said plurality of disk devices, a plurality of volumes being assigned to said disk devices, wherein a disk array controller controls said disk devices, wherein assignment of new disk cache areas to said data is performed by said disk cache controlling method comprising the steps of:
- dividing each of said volumes into areas with an arbitrary fixed length;
- calculating an access frequency to data in each of the divided areas of each of said volumes;
- determining the divided areas having higher access frequencies compared with an average access frequency for each of the volumes based on a distribution of the calculated access frequencies;
- and
- changing assignment of said disk cache areas to said divided areas of each of said volumes according to an access characteristic divided areas determined in said determining step,
- wherein said disk cache areas having stored data the access frequencies to which have been the lowest are reassigned to said divided areas.
A disk cache controlling method in a disk array system including a plurality of disk devices and a disk cache, data being divided and stored into said plurality of disk devices, a plurality of volumes being assigned to said disk devices, wherein each of said volumes is divided in to a plurality of areas each having an arbitrary fixed length, wherein a host connected to said disk array system transfers a command including an application identifier, and said disk array system acquires an access frequency to data in each of said divided areas indicated by said application identifier, said disk cache controlling method comprising a step of:
- determining whether the access frequencies of the divided areas indicated by said application identifier are higher than an average access frequency of whole areas;
- depriving, at the time of assignment of new disk cache areas to the divided areas of each of the volumes, said disk cache areas of use of said divided areas according to a result of the determining step,
- wherein a disk cache area having stored data the access frequency to which is the lowest is deprived and reassigned to a divided area having the lowest access frequency.
A disk array system comprising:
- a plurality of disk devices;
- a disk cache;
- and
- a disk array controller connectable to said plurality of disk devices and said disk cache,
- wherein data are divided and stored into said plurality of disk devices, a plurality of volumes are assigned to said disk devices,
- wherein a disk array controller divides each of said volumes into areas with an arbitrary fixed length, calculates an access frequency to data in each of the divided areas, determines the divided areas having higher access frequencies than an average access frequency for each of the volumes based on a distribution of the calculated access frequencies of each of the volumes, and changes assignment of new disk cache areas to said divided areas of each of said volumes according to an access characteristic of the determined areas,
- wherein said disk cache areas having stored data the access frequencies to which have been the lowest are reassigned to said divided areas.
A system, comprising:
- a disk array system including a plurality of disk devices and a disk cache, data being divided and stored into said plurality of disk devices, a plurality of volumes being assigned to said plurality of disk devices, wherein each of said volumes is divided into a plurality of divided areas each having an arbitrary fixed length, and
- a host, being connected to said disk array system, transfers a command including an application identifier,
- wherein said disk array system acquires an access frequency to data in each of said divided areas indicated by said application identifier, and said disk array system further comprising:
- means for determining whether the access frequencies of the divided areas indicated by said application identifier are higher than the average access frequency of whole areas;
- means for controlling said disk cache so that, at the time of assignment of disk cache areas to the divided areas of each of the volumes, said disk cache areas are deprived according to a result of the determining means,
- wherein a disk cache area having stored data to which access frequency is the lowest is deprived and reassigned to the divided area.
A disk cache controlling method in a storage system including a disk device in which data is stored and a disk cache, wherein assignment of new disk cache areas to said data is performed by the steps of:
- segmenting said disk device into areas each having an arbitrary fixed length;
- calculating an access frequency to data in each segmented area of said disk device;
- determining the areas having higher access frequencies compared with an average access frequency for the disk device based on a distribution of the calculated access frequencies;
- and
- assigning said disk cache areas to said segmented areas according to a result of the determining step,
- wherein said disk cache areas having stored data the access frequencies to which have been the lowest are reassigned to said segmented areas.
A disk cache controlling method in a storage system including a disk device in which data is stored and a disk cache, wherein assignment of new disk cache areas to said data is performed by the steps of:
- segmenting said disk device into areas each having an arbitrary fixed length;
- calculating an access frequency to data in each segmented area of said disk device a product of a number of accesses and a weight being set to said access frequency, said weight being larger as said area accessed separates further away from an initial position of a head of said disk device;
- determining the segmented areas having higher access frequencies compared with an average frequency for said disk device based on a distribution of the calculated access frequencies;
- and
- assigning said disk cache areas to said segmented areas according to a result of the determining step,
- wherein said disk cache areas having stored data the access frequencies to which have been the lowest are reassigned to said segmented areas.
A disk cache controlling method in a storage system including a disk device in which data is stored and a disk cache, wherein assignment of new disk cache areas to said data is performed by the steps of:
- segmenting said disk device into areas each having an arbitrary fixed length;
- calculating an access frequency to data in each segmented area of said disk device, a product of a number of accesses and a weight being set to said access frequency, said weight being larger as said area accessed approaches nearer to an inner side of a drive of said disk device;
- determining the segmented areas having higher access frequencies compared with an average access frequency for said disk device based on a distribution of the calculated access frequencies;
- and
- assigning said disk cache areas to said segmented areas according to a result of the determining step,
- wherein said disk cache areas having stored data the access frequencies to which are the lowest are reassigned to said segmented areas.
A storage system including a disk device in which data is stored and a disk cache, comprising:
- means for segmenting said disk device into areas each having an arbitrary fixed length;
- means for calculating an access frequency to data in each segmented area of said disk device;
- means for determining the segmented areas having higher access frequencies compared with an average access frequency for said disk device based on a distribution of the calculated access frequencies;
- and
- means for controlling said disk cache so that assignment of new disk cache areas to said segmented areas according to a result in the determining step,
- wherein said disk cache areas having stored data the access frequencies to which are the lowest are reassigned to said segmented areas.
A storage system including a disk device in which data is stored and a disk cache, comprising:
- means for segmenting said disk device into areas each having an arbitrary fixed length;
- means for calculating an access frequency to data in each segmented area of said disk device;
- means for determining the segmented areas having higher access frequencies compared with an average access frequency for the disk device based on a distribution of the calculated access frequencies;
- and
- means for controlling disk cache assignment of new disk cache areas to said segmented areas according to a result in the determining means,
- wherein said disk cache areas having stored data to which access frequencies are the lowest are reassigned to said segmented areas;
- and
- means for setting a product of a number of accesses and a weight of said access frequency, said weight being larger as said area accessed separates farther away from an initial position of a head of said disk device,
- wherein a disk cache area assigned to said segmented area is made less likely to be deprived.
A storage system including a disk device in which data is stored and a disk cache, comprising:
- means for segmenting said disk device into areas each having an arbitrary fixed length;
- means for calculating an access frequency to data in each segmented area of said disk device;
- means for determining the segmented areas having higher access frequencies compared with an average access frequency for said disk device based on a distribution of the calculated access frequencies;
- means for controlling disk cache assignment of new disk cache areas to said segmented areas according to a result in the determining means,
- wherein said disk cache areas having stored data the access frequencies to which have been the lowest are reassigned to said segmented areas;
- and
- means for setting a product of a number of accesses and a weight of said access frequency, said weight being larger as said area accessed approaches nearer to an inner side of a drive of said disk device,
- wherein a disk cache area assigned to said segmented area is made less likely to be deprived.
A disk cache controlling method in a disk array system including a plurality of disk devices in which data is stored and a disk cache, a plurality of volumes being assigned to said plurality of disk devices, wherein a disk array controller controls said disk devices, wherein assignment of disk cache areas is performed by said disk cache controlling method comprising the steps of:
- dividing each of said volumes into areas with an arbitrary fixed length;
- specifying a plurality of I/O working sets based on distribution of access frequencies of respective divided areas;
- comparing widths of the I/O working sets corresponding to the divided areas within each volume of said plurality of volumes;
- and
- assigning said disk cache areas to a narrower I/O working set with a higher priority.
A disk cache controlling method in a disk array system including a plurality of disk devices in which data is stored and a disk cache, a plurality of volumes being assigned to said disk devices, wherein a disk array controller controls said disk devices, wherein assignment of disk cache areas is performed by said disk cache controlling method comprising the steps of:
- dividing each of said volumes into areas with an arbitrary fixed length;
- specifying a plurality of reference areas based on distributions of access frequencies of respective divided areas;
- comparing widths of the reference areas corresponding to the divided areas within each of said volumes, said reference areas being referred to by each application of a plurality of applications on a host;
- and
- assigning, with the highest priority, said disk cache areas to an application the reference area of which is the narrowest.
A disk cache controlling method in a disk array system including a plurality of disk devices in which data is stored and a disk cache, wherein assignment of disk cache areas is performed by the steps of:
- segmenting each of said disk devices into areas with an arbitrary fixed length;
- specifying a plurality of I/O working sets based on distribution of access frequencies of respective segmented areas;
- comparing widths of the I/O working sets, corresponding to the segmented areas, assigned to each job of a plurality of jobs;
- and
- assigning, with the highest priority, said disk cache areas to a job the I/O working set of which is the narrowest.
A disk cache controlling method in an information processing device including a disk device in which data is stored and a disk cache, comprising a step of:
- segmenting said disk device into a plurality of areas each having an arbitrary fixed length;
- and
- assigning, with the higher priority, disk cache areas to said segmented areas within a volume assigned to said disk device, separated farther away from a head initial position of a drive of said disk device.
Dependencies are inferred from the claim text.