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AssigneeInternational Business Machines Corporation
InventorNeeta Garimella
Estimating the term…
A program, method and system are disclosed for managing a snapshot backup restore through a hardware snapshot interface, i.e. a hardware-driven snapshot restore, based upon a software-driven snapshot backup, e.g. created with software such as volume shadow copy service (VSS). When conventional hardware-driven snapshot restores are performed using a snapshot backup that was created using the VSS-based software such as copy services, data access issues can arise, due to the operating system assigning of a new disk signature to the disk being restored. This problem can be overcome by temporarily storing the original disk signature and then overwriting the new, incorrect disk signature after initializing the restore. This can ensure that the operating system identifies the source LUNs (and accordingly, the drive letter and mount points of the disk) using the same disk signature as before the restore.
A computer program embodied on a computer readable medium, comprising:
A method comprising the steps of:
A backup system, comprising:
Dependencies are inferred from the claim text.
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From the US filing history. Foreign family members aren’t listed.
At system level: using file system or storage system metadata
Management of the backup or restore process: backup restoration techniques
Point-in-time backing up or restoration of persistent data: hardware arrangements for backup
Indexing scheme relating to error detection, to error correction, and to monitoring: using snapshots, i.e. a logical point-in-time copy of the data
About 1 year 8 months of term left · ends 18 Jun 2028 (estimated)
1. Field of the Invention
This invention relates to data backups systems. Particularly, this invention relates to restoring data backups with hardware and software backup and restore processes such that consistency of disk signatures is maintained before and after restore.
2. Description of the Related Art
Referring now to the drawings in which like reference numbers represent corresponding parts throughout:
FIG. 1A illustrates an exemplary computer system that can be used to implement embodiments of the present invention;
FIG. 1B illustrates a typical distributed computer system which may be employed in an typical embodiment of the invention;
1. Overview
As previously mentioned, VSS is a Microsoft platform that operates to assist driving both hardware as well as software based snapshot from a single interface. But, VSS can not create a snapshot by itself and requires a snapshot service to support it. Accordingly, the underlying technology may be hardware-based for both the backup as well as restore. (A typical VSS user may not even be aware of the underlying snapshot technology.) The previously described disk signature problem arises from a processing difference between the backup creation and restore path for a snapshot backup. Specifically, when TSM copy services creates a backup, the backup is processed through the VSS APIs to create the snapshot backup. This type of processing to create the backup may be termed software-driven. However, on the restore side, the snapshot has to be created outside of the VSS using APIs provided by the hardware, since VSS does have the capability to allow instant restore. This type of processing to restore a backup may be termed hardware-driven. So there exists a problem related to the disk signature that is solved by this invention.
Embodiments of the invention can operate as part of a distributed data backup system for a networked computer system that utilizes hardware-driven snapshot restore by hardware, such as the IBM Tivoli Storage Manager, from a snapshot created by software, such as Microsoft Volume Shadow Copy Services (VSS). Such software-driven snapshots maintain a different LUN from the LUN of the original disk that is being backed up. The LUN stores the disk signature, which assists the operating system to identify the disk being used. (A disk may be defined as any device that stores data.) The target LUN (the LUN that the software maintains to store backup data) is distinct from the source LUN (the LUN that represents the disk in use). This technique of maintaining multiple LUNs is necessary when such software copy services create the backups to allow both LUNs to be accessed simultaneously by the software. Otherwise, the copy service could not distinguish between the two sets of data if they were assigned the same LUN. When a snapshot-based restore is initiated by the hardware, the source LUN is replaced with the target LUN. However, when the source LUN is replaced with the target LUN, the operating system identifies the disk being restored as a new disk and assigns it a new disk signature. This problem occurs due to the use of multiple LUNs by the software-driven snapshot and their use with a hardware-driven snapshot restore.