Data processing: database and file management or data structures – Database design – Data structure types
Reexamination Certificate
1999-02-26
2001-12-11
Breene, John (Department: 2177)
Data processing: database and file management or data structures
Database design
Data structure types
Reexamination Certificate
active
06330570
ABSTRACT:
TECHNICAL FIELD
The present invention relates to data backup systems, and particularly to increasing the reliability of data backup systems.
BACKGROUND ART
When a pre-defined set of data, or ‘data set’, is to be transferred from a host system's internal mass storage, such as a hard disk, to a secondary backup device, such as a tape drive, the procedure is known as a ‘backup job’. In most known backup application software packages there are two basic methods by which such a backup job may be initiated; manually or scheduled.
In the case of manual backup, an operator enacts the backup by executing backup application software on the host system, which operates immediately to backup selected, stored data files to, for example, tape.
When a backup job is scheduled, an operator executes the backup application software and configures software to run the backup job at a pre-defined time, such as ‘every night at midnight’ or ‘every Friday at 1:00 am’, or, in general, when the data to be backed up is not being accessed by anyone. From the moment that the job is set up, the backup software sits substantially idle until the backup date and time arrives. At this point, the software establishes communications with the backup device, for example over an interface and connecting bus (e.g. SCSI), and then transfers the data.
At the point that the host system starts to actually run the backup job, the process of completing the job may be prone to failure for many different reasons. These might include:
a communications error such as a software driver becoming corrupted or deactivated;
a connectivity problem such as the backup device has its data communications path broken (e.g. the SCSI cable has been unplugged);
the backup device is powered off (e.g. somebody has accidentally pulled out the mains cable);
a hardware failure in the backup device;
the backup medium is not present (e.g. the tape has been taken out); or
the backup medium cannot be written to (e.g. it is write-protected, worn out or full).
If one of these errors occurs, then the backup job will not be completed and the operator will typically not know about it until he observes an error message on the host system console, usually first thing the following morning. By the time the operator reads the message, no backup job has been run successfully and the system's data has been left unprotected. It is then too late to start another backup job as the system is now in use for everyday work tasks.
DISCLOSURE OF THE INVENTION
The present inventors, in appreciating the potential serious implications of a failed backup job, have developed an effective solution, to be described below, which substantially reduces the risk of a backup job failing.
As such, according to one aspect, the present invention provides a backup system configurable to enact a pre-backup check, to verify that a proposed backup job can be completed, in advance of enacting the proposed backup job, the system comprising means to produce a warning message in the event of a determination that there is a likelihood that the proposed backup job will not complete successfully.
Such a system greatly reduces the risk of a backup job failing, by instigating the pre-backup check. Within the meaning of the present description, any backup checks that happen automatically as part of a backup job, at substantially the same time as the backup job, would not be classed as a pre-backup check.
The pre-backup check may verify that data can be written to specified backup apparatus. Verification for this purpose might be achieved by simply signalling to the backup apparatus, for example using a SCSI ‘test unit ready’ command. If the backup apparatus responds with the correct signal, then the backup system assumes that the backup apparatus is operational. If the backup apparatus responds with an unexpected signal, or does not respond at all, then the backup system assumes that the backup apparatus will not operate correctly, and, as a result, generates a warning message. An alternative approach to verify the correct operation of the backup apparatus would be to attempt writing some data to the backup apparatus and media.
Additionally, or alternatively, the pre-backup check may verify that data forming at east part of the defined data set can be accessed by the system. For this, the backup system might select, for example, one data file from the defined data set and attempt to access that file. Successful access leads the backup system to assume that file system access is possible.
In one embodiment, for the pre-backup check, the system may enact a relatively small portion of the proposed backup job in order to verify that the proposed backup job may be completed successfully. For example, if the proposed backup job is defined to back up a large number of data files, the check might involve reading one of the files defined by the data set and writing the file to the backup device, such as a tape drive. In this way, the communications channels between both the file system and the backup apparatus are checked. A failure in reading the file, or writing the file to the backup apparatus, triggers a warning message. Alternatively, rather than reading a whole file, the check might involve reading a small part of a file, particularly when files can be large.
The pre-backup check and the proposed backup job can, preferably, both be scheduled. In a typical scenario, the pre-backup check would be scheduled to operate as late as possible in the working day, for example just before the time an operator is due to leave work in the evening. The actual backup job would typically be scheduled to occur at a time when no computer operators would be expected to be at work, for example at 1:00 am in the morning. Thus, failure at the pre-backup check stage would warn the operator, before he goes home, to take remedial action in order to ensure that the backup job at 1:00 am is able to complete successfully.
The pre-backup check may be schedulable to occur in advance of at least one scheduled instance of the proposed backup job. In this case, for example, a pre-backup check could be scheduled to occur before at least one scheduled backup, where the backup job might be scheduled to happen each day at 1:00 am.
In a preferred embodiment, however, the pre-backup check can be scheduled to occur in advance of every scheduled instance of the proposed backup job. Thus, for minimum risk, the pre-backup check would be carried out every day before every backup job.
The pre-backup check may include the step of estimating the required capacity of backup media for the proposed backup job. In particular, the pre-backup check may estimate the required capacity on the basis of previous, completed backup jobs.
In a preferred embodiment to be described, the backup system typically comprises a host computer running application software operative to provide a graphical user interface (GUI) having backup operator-configurable options which allow a backup operator to configure the independent operation of both the pre-backup check and the proposed backup job.
In a preferred embodiment to be described, the backup system also typically provides a graphical warning message in the event the pre-backup check determines that a backup job may not complete successfully.
In an alternative embodiment, the backup system provides a graphical warning message on a remote computer terminal in the event the pre-backup check determines that a backup job may not complete successfully.
The present invention also provides method of backing up data, comprising the steps of:
scheduling a backup system to enact a pre-backup check to verify that a proposed backup job can be completed;
scheduling a backup system to enact a backup job to occur at a time after the pre-backup check;
generating a warning message in the event the pre-backup check determines that there is likelihood that the backup job will not be successful.
Other aspects and embodiments of the present invention are described and claimed hereunder.
REFERENCES:
patent: 4634110 (1987-01-01)
Breene John
Hewlett--Packard Company
Rayyan Susan
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