Managing data storage devices connected to a digital computer
First Claim
1. In the machine-implemented method of operating a data-storage hierarchy having a plurality of primary and secondary data-storage volumes, each of said volumes being addressable and having a given plurality of addressable data-storage areas for respectively storing a predetermined amount of data, each of said primary volumes having relatively rapid-access characteristics for data stored therein while each of said secondary volumes having relatively slow access characteristics for data stored therein, means coupled to said volume for transferring data therebetween;
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transferring data from a first one of said secondary volumes to a first one of said primary volumes for constituting a recall of data stored in said first one secondary volume;
transferring data from a second one of said primary volumes to a second one of said secondary volumes for constituting a migration of data stored in said second one primary volume;
initiating a one of a said migrations of data and a one of said recalls of data, respectively, as a migration step and as a recall step;
upon initiating each said migration step, first determining the accessibility of said second one of said secondary volumes which is to receive and store data to be migrated, upon determining said second one of said secondary volumes is accessible, performing said migration step;
upon determining that said second one of said secondary volumes is not accessible, assigning a third one of said secondary volumes to receive and store said data to be migrated and then performing said migration step to said third one of said secondary volumes;
upon initiating a said recell step, first determining the accessibility of said first one of said secondary volumes, if said first one of said secondary volumes is accessible, then performing said recall step, otherwise setting a flag bit indicating that the initiated recall is being delayed;
during said migration step, repeatedly sensing said flag bit for determining if a recall is being delayed;
when said flag bit is reset, continuing said migration step, otherwise when the flag bit is set, determining if said second one of said secondary volumes is to be said first one of said secondary volumes;
if not, continuing the migration step, otherwise selecting a fourth one of said secondary volumes to receive a remaining portion of the data to be migrated and continuing said migration step with said fourth one of said secondary volumes for receiving and storing said remaining portion; and
then performing said recall step with said second one of said secondary volumes.
1 Assignment
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Accused Products
Abstract
A storage-management program, executable in one host or simultaneously in a plurality of hosts, manages concurrently executing migration, recall, and recycle (such as defragmentation) tasks. Accesses to data storage volumes (tape, disks, etc.) are managed in accordance with predetermined contention resolution procedures and priorities. Certain tasks are non-interruptible.
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Citations
14 Claims
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1. In the machine-implemented method of operating a data-storage hierarchy having a plurality of primary and secondary data-storage volumes, each of said volumes being addressable and having a given plurality of addressable data-storage areas for respectively storing a predetermined amount of data, each of said primary volumes having relatively rapid-access characteristics for data stored therein while each of said secondary volumes having relatively slow access characteristics for data stored therein, means coupled to said volume for transferring data therebetween;
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including the steps of; transferring data from a first one of said secondary volumes to a first one of said primary volumes for constituting a recall of data stored in said first one secondary volume; transferring data from a second one of said primary volumes to a second one of said secondary volumes for constituting a migration of data stored in said second one primary volume; initiating a one of a said migrations of data and a one of said recalls of data, respectively, as a migration step and as a recall step; upon initiating each said migration step, first determining the accessibility of said second one of said secondary volumes which is to receive and store data to be migrated, upon determining said second one of said secondary volumes is accessible, performing said migration step;
upon determining that said second one of said secondary volumes is not accessible, assigning a third one of said secondary volumes to receive and store said data to be migrated and then performing said migration step to said third one of said secondary volumes;upon initiating a said recell step, first determining the accessibility of said first one of said secondary volumes, if said first one of said secondary volumes is accessible, then performing said recall step, otherwise setting a flag bit indicating that the initiated recall is being delayed; during said migration step, repeatedly sensing said flag bit for determining if a recall is being delayed;
when said flag bit is reset, continuing said migration step, otherwise when the flag bit is set, determining if said second one of said secondary volumes is to be said first one of said secondary volumes;
if not, continuing the migration step, otherwise selecting a fourth one of said secondary volumes to receive a remaining portion of the data to be migrated and continuing said migration step with said fourth one of said secondary volumes for receiving and storing said remaining portion; andthen performing said recall step with said second one of said secondary volumes. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. In a data processing system having a data processing unit connected to a plurality of data storage apparatus including disk data storage apparatus for transferring data between the data processing unit and said plurality of data storage apparatus and between said plurality of data storage apparatus;
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the improvement including, in combination; a control memory in said data processing unit for storing program indicia to sequence said data processing unit through a series of machine operations including storage managing machine operations (SMO) which transfer data between said plurality of data storage apparatus; first program indicia stored in said control memory for sequencing said data processing unit in SMO to designate first predetermined ones of said data storage apparatus, including said disk data storage apparatus, as primary data storage volumes; second program indicia stored in said control memory for sequencing said data processing unit for transferring data between said primary data storage volumes and said data processing unit; third program indicia stored in said control memory for sequencing said data processing unit in SMO to designate second predetermined ones of said data storage apparatus as secondary data storage volumes; migration program indicia stored in said control memory for sequencing said data processing unit in SMO to transfer data from a first one of said primary data storage volumes to a first one of said secondary data storage volumes; recall program indicia stored in said control memory for sequencing said data processing unit in SMO for transferring data from a second one of said secondary data storage volumes to a second one of said primary data storage volumes; volume control program indicia stored in said control memory for sequencing said data processing unit in SMO to establish and maintain listings of said data storage volumes including indications of whether each data storage volume is currently being accessed and which of said recall or migration program indicia sequenced the data processing unit to access each such data storage volume; work element program indicia stored in said control memory for sequencing said data processing unit to schedule data transfers between said first primary and first secondary data storage volumes and between said second primary and second secondary data storage volumes; scheduling program indicia stored in said control memory for sequencing said data processing unit to activate said work element program indicia to schedule said data transfers and to activate said migration and recall program indicia; said migration and recall program indicia including checking program indicia for sequencing said data processing unit after said work element program indicia sequenced the data processing unit to activate said migration and recall program indicia, respectively, to access said listings and determining whether any data storage volume needed for the just-activated migration or recall program indicia sequencing is currently being accessed in SMO and for what purpose, and also including program indicia for sequencing said data processing unit to select another one of said secondary data storage volumes whenever said second secondary data storage volume is currently being accessed by said data processing unit in a sequence enabled by other of said program indicia than said migration program indicia and to delay said recall program indicia sequencing whenever said first secondary data storage volume is currently being accessed by said data processing unit in a sequence enabled by other said program indicia than said recall program indicia; said recall program indicia further including flag indicia for setting a flag whenever said delay occurs; and said migration program indicia further including flag sensing indicia for sequencing said data processing unit to periodically sense for said flag and when said flag is sensed as being set, then sequencing said data processing unit to release the second secondary data storage volume for use by the flag setting recall program indicia and to select another one of said secondary data storage volumes as a second secondary data storage volume to receive and store any remaining portions of data to be transferred from said second primary data storage volume as sequenced by said migration program indicia. - View Dependent Claims (11, 12, 13, 14)
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Specification