Data set level mirroring to accomplish a volume merge/migrate in a digital data storage system
First Claim
1. A method for combining extents of a source data set, with minimal down time imposed on applications accessing the source data set, the source data set having a corresponding name, source DASD device(s) and one or more extent locations on the source DASD device(s), the method comprising the steps of:
- a) assessing the source data set to be migrated, the volume(s) it resides on, and the total space it occupies;
b) allocating space for a corresponding target data set using the total source space as a primary allocation request and using the original source data set name;
c) designating one or more target locations in the allocated space and assigning each source data set extent location to a respective one or more of the designated target locations;
d) starting monitor programs on any images that can write to any of the identified source volumes in order to detect a subsequent change to the source data set;
e) storing an indication of each source data set track detected by a monitor program as having changed;
f) begin copying the source data set in accordance with said assignment of each source data set extent so as to form the corresponding target data set;
g) while copying the source data set, periodically re-synchronizing source and target tracks detected by the monitor programs as having changed after having been previously copied;
h) upon substantial completion of said copying, signaling an operator that closing the source data set is requested;
i) recognizing that the source data set is closed thereby commencing a down time window;
j) during the downtime window, finally re-synchronizing the source and target tracks detected by the monitor programs as having changed after having been previously copied;
k) during the downtime window, accommodating any allocation changes affecting the source data set that occurred since the initial assessment of the source data set;
l) changing catalog entries to reflect new target data set volumes; and
m) signaling a user that the target data set may be opened, thereby terminating the down time window.
14 Assignments
0 Petitions
Accused Products
Abstract
Users of Mainframe computers running under IBM'"'"'s MVS operating systems have a need to merge migrate data from multiple smaller DASD devices (disk volumes) to larger DASD devices, and/or to migrate data in order to combine data set extents. A method is disclosed for migrating data where a volume merge is involved, and/or when combining of extents is desired, that minimizes the down time of applications using the involved data while satisfying MVS rules for volume and catalog meta-data files as well as data extent limitations. The method may be implemented such that source and target volumes need not be in like manufacturer DASD devices.
45 Citations
55 Claims
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1. A method for combining extents of a source data set, with minimal down time imposed on applications accessing the source data set, the source data set having a corresponding name, source DASD device(s) and one or more extent locations on the source DASD device(s), the method comprising the steps of:
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a) assessing the source data set to be migrated, the volume(s) it resides on, and the total space it occupies; b) allocating space for a corresponding target data set using the total source space as a primary allocation request and using the original source data set name; c) designating one or more target locations in the allocated space and assigning each source data set extent location to a respective one or more of the designated target locations; d) starting monitor programs on any images that can write to any of the identified source volumes in order to detect a subsequent change to the source data set; e) storing an indication of each source data set track detected by a monitor program as having changed; f) begin copying the source data set in accordance with said assignment of each source data set extent so as to form the corresponding target data set; g) while copying the source data set, periodically re-synchronizing source and target tracks detected by the monitor programs as having changed after having been previously copied; h) upon substantial completion of said copying, signaling an operator that closing the source data set is requested; i) recognizing that the source data set is closed thereby commencing a down time window; j) during the downtime window, finally re-synchronizing the source and target tracks detected by the monitor programs as having changed after having been previously copied; k) during the downtime window, accommodating any allocation changes affecting the source data set that occurred since the initial assessment of the source data set; l) changing catalog entries to reflect new target data set volumes; and m) signaling a user that the target data set may be opened, thereby terminating the down time window. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for data set-level mirroring of a selected source data set while minimizing downtime of applications accessing the source data set, the method comprising:
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identifying extents allocated to the source data set, each extent comprising a set of at least one DASD track; allocating within a target data set at least a number of extents needed to store the identified extents of the source data set; copying each track of an extent of the source data set to an extent of the target data set; in response to any tracks of the source data set being changed by an application during the copying step, recopying the changed tracks from the source data set to the target data set; commencing a downtime window in which applications may no longer access the source data set; and in response to an allocation change being made to the source data set since the allocating step, performing a corresponding allocation change to the target data set during the down-time window. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. A computer-readable medium storing computer-readable program code for performing a method for data set-level mirroring of a source data set while minimizing downtime of applications accessing the source data set, the stored computer program code comprising:
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computer-readable program code for identifying extents belonging to the source data set, each extent comprising a set of tracks; computer-readable program code for allocating within a target data set at least a number of extents needed to store the identified extents of the source data set; computer-readable program code for copying each track of an extent of the source data set to an extent of the target data set; computer-readable program code for in response to any tracks of the source data set being changed by an application during the copying step, recopying the changed tracks from the source data set to the target data set; computer-readable program code for commencing a downtime window in which applications may no longer access the source data set; and computer-readable program code for performing an allocation change to the target data set in response to an allocation change being made to the source data set since the initial allocating step. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46)
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47. A method for data set-level migrating a selected source data set under a Multiple Virtual Storage (MVS) operating system while minimizing downtime of the source data set, the method comprising:
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(a) assessing the source data set to be migrated so as to identify a set of source data set tracks on which the data set is stored; (b) storing initial meta-data that reflects extent locations of the source data set tracks; (c) initially allocating a target data set with at least sufficient space to store the source data set tracks; (d) beginning sequential copying of only the source data set tracks to the target data set; (e) while the sequential copying proceeds, beginning monitoring to detect any changes to a source data set track after the track was last sequentially copied, thereby identifying as a modified track one that requires re-copying; (f) continuing the sequential copying of source data set tracks until all of the source data set tracks have been copied, and all modified tracks have been re-copied; (g) after completion of the sequential copying, requesting that a user close and unallocate the source data set; (h) continuing said monitoring to detect and identify any modified source data set tracks until the source data set has been closed and unallocated; (i) while waiting for the source data set to be closed and unallocated, re-copying any identified modified track; (j) responsive to an indication that the source data set has been closed and unallocated, effecting a final re-synchronization step by re-copying any modified track not yet re-copied; (k) checking to detect any allocation change to the source data set since initially allocating the target data set, by comparing current meta-data describing the source data set to the initial meta-data stored at the beginning of the process; (l) in response to detecting an allocation change having been made to the source data set after the target data set was initially allocated, adjusting the target data set to accommodate the allocation change; (m) updating a corresponding catalog and system meta-data describing the source data set to point to the target data set; and
then(n) signaling release to open the target data set. - View Dependent Claims (48, 49, 50, 51, 52, 53, 54, 55)
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Specification