Electrical computers and digital processing systems: memory – Storage accessing and control – Control technique
Reexamination Certificate
2000-11-27
2003-06-24
Portka, Gary (Department: 2188)
Electrical computers and digital processing systems: memory
Storage accessing and control
Control technique
C711S171000
Reexamination Certificate
active
06584551
ABSTRACT:
FIELD OF THE INVENTION
The present invention generally relates to the field of snapshot repositories utilized in memory or storage systems such as RAID (Redundant Array of Independent Disks) storage systems and the like, and more particularly to a method for automatically dynamically expanding a snapshot repository volume.
BACKGROUND OF THE INVENTION
Multiple drive storage systems such as RAID storage systems or the like commonly used by networked computing systems typically include a snapshot repository for storing a collection of information about the storage system. This collection of information, commonly referred to in the art as a “snapshot”, allows data stored by the storage system in the event of failure thereby allowing substantially instant backup of data in the storage system. Snapshots are periodically saved to the snapshot repository as data stored in the storage system is altered so that the repository information is kept current.
Presently, when a user, such as the system administrator of the storage system, or the like, defines a repository for a snapshot, that user must specify the exact size of the repository volume (e.g., as a set amount of memory such as 30 GB (gigabytes)). However, this requirement forces the user to anticipate the write mix of the I/O (input/output) pattern to the base volume. In other words, if the repository runs out of space because too many write operations were performed to the base volume, the snapshot becomes invalid or fails. Should this event occur, user intervention is required to increase the size of the repository, or, alternately, to make the snapshot valid via other means.
Consequently, it would be desirable to provide a means of automatically and dynamically expanding the size of the snapshot repository volume based on user defined parameters.
SUMMARY OF THE INVENTION
Accordingly, the present invention is directed to a system and method for dynamically expanding a snapshot repository volume. In this manner, automatic scaling of the repository volume may be provided so that the exact initial size of the repository volume need not be known. Further, the snapshot repository may be allowed to grow with the usage pattern of the system while keeping the repository sized to a relatively small and appropriate level.
In accordance with a first aspect of the invention, a method for dynamically expanding a snapshot repository is disclosed. The method includes the steps of monitoring the snapshot repository for determining if the amount of information stored in the snapshot repository has reached a predetermined volume increase threshold. If a determination is made that the volume increase threshold has been reached, the volume of the snapshot repository is automatically increased. In an exemplary embodiment, the method also includes the steps of monitoring the snapshot repository for determining if the amount of memory utilized by information stored in the snapshot repository has reached a predetermined maximum snapshot repository volume threshold and providing a warning if the maximum snapshot repository volume threshold is reached. In this manner, the method allows the size of the repository volume to be automatically increased each time a predetermined volume increase threshold is reached up to a predetermined maximum volume.
In accordance with a second aspect of the invention, a system for storing a snapshot of a memory is disclosed. The system includes a snapshot repository suitable for storing the snapshot and a controller for controlling the snapshot repository. The controller is capable of monitoring the snapshot repository for determining if the amount of memory utilized by information stored in the snapshot repository has reached a predetermined volume increase threshold and increasing the volume of the snapshot repository if the volume increase threshold is determined to have been reached. The controller may further monitor the snapshot repository for determining if the amount of memory utilized by information stored in the snapshot repository has reached a predetermined maximum snapshot repository volume threshold and provide a warning if the maximum snapshot repository volume threshold is (or is about to be) reached.
In exemplary embodiments of the present invention, the expansion behavior of the snapshot directory may be specified at the time it is created. This may be accomplished by allowing a user, for example, the system administrator, to define such parameters as the initial size of the snapshot repository volume, the maximum size of the snapshot repository volume, the amount of incremental increase of the snapshot repository volume, the volume increase threshold, the maximum snapshot repository volume threshold, and the like.
It is to be understood that both the forgoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention as claimed. The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate an embodiment of the invention and together with the general description, serve to explain the principles of the invention.
REFERENCES:
patent: 6131148 (2000-10-01), West et al.
patent: 6182198 (2001-01-01), Hubis et al.
patent: 6311193 (2001-10-01), Sekido
patent: 6330570 (2001-12-01), Crighton
patent: 6341341 (2002-01-01), Grummon et al.
LSI Logic Corporation
Portka Gary
Suiter & Associates
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