Advanced Data Recovery For IBM AIX Environments
Alan Arnold, 04/02/2010, posted in "Analysis"
Alan Arnold is the EVP and CTO for Vision Solutions and is responsible for the global technology, services and support strategy for the business. Alan joined Vision in 2000, ...more info
Alan Arnold is the EVP and CTO for Vision Solutions and is responsible for the global technology, services and support strategy for the business. Alan joined Vision in 2000, and since joining the company, he has served in a variety of positions including EVP of Technologies and President and Chief Operating Officer of worldwide operations. Prior to joining Vision Solutions, Alan was a senior technology executive in the management consulting practice of Ernst & Young. Alan served as the firm’s subject matter expert for IBM technology and e-commerce solutions, and was one of the founders and managers of the Ernst & Young Advanced Development Center (ADC). Prior to E&Y, Alan worked at StorageTek (XL/Datacomp) as the National Director of Technologies, and prior to this, he worked in several other companies in technology and management roles. Alan is recognised as an expert in advanced technologies, business process improvements and managed availability solutions. He has authored or co-authored five books on technology and business topics that have been published worldwide. He has written numerous articles for some of the leading publications in the industry, and has had his work presented to the United States Senate Technology subcommittee and State of California. ...less info
For the most part, traditional tape-based backup and recovery techniques accomplish their rudimentary goals. Nonetheless, they suffer a number of drawbacks.
The backup process itself is at the heart of one of the problems. Applications typically must be stopped or curtailed, possibly for hours, while data is backed up. At one time, this could be done on weekends or evenings without affecting business activity. However, for many companies, globalized operations, competitive demands to keep factories running longer and Web-based sales and service have eliminated these backup windows.
The issue of disappearing backup windows pales in comparison with the problems that can occur when recovering a system from tape. The tapes have to be retrieved, the data must be loaded and then the system must be reconfigured. Even using modern high-speed tape drives, recovering an entire data center can take hours or even days. That is far too long for many organisations that are dependent on their information systems.
Lack of recovery completeness is another problem. Backup tapes are typically created at night and then shipped off-site where they will be safe from a disaster that strikes the data center. Updates applied during the next day will not have been written to any backup tape and, therefore, may be lost should a disaster occur.
High availability (HA) technologies, which maintain online replicas of production servers, eliminate the drawbacks of tape-based backups. And if the replica is far enough from the primary server, a disaster is unlikely to affect both locations. If the primary system becomes unavailable or needs to be taken offline for maintenance, users can be switched to the backup.
However, neither tape-based backups nor standard HA solutions protect against one type of threat: If an human error, software bug, disk failure or virus attack deletes or corrupts data that was recently created or updated there may be no way to recover that data.
Because tape-based backups are produced only at night, the tape cannot be used to recover data that was added or changed the next day. Standard HA software can’t help in this situation either. The software dutifully replicates all updates and deletions, even if they were accidental or malicious. Thus, data will be corrupted equally on both the primary and backup servers.
Fortunately, one class of software that is now available for AIX can solve this thorny data recovery problem. Continuous data protection, or CDP, is a flexible disk-based technology that enables organisations to quickly and easily recover data as it existed at any point in time. This earlier version of the data can then be restored to the production environment.
There are two types of CDP: true CDP and near-CDP. True CDP captures every data write performed on a primary system, immediately transfers those writes to a secondary disk and stores each of them separately rather than applying them to copies of the production files. Consequently, true CDP allows you to “undo” updates and deletions by recovering data to any point in time.
In contrast, near-CDP copies data at particular points in time, typically when a file is saved or closed. The copy frequency varies depending on how the CDP software defines these recovery points and on the nature of the applications updating the data. The copy intervals may be a matter of minutes or seconds, but they might also be as long as several hours.
In some circumstances, this may reduce the volume of sustained network traffic somewhat when compared to true CDP, but it may not provide adequate data protection for organisations that must comply with strict regulations or governance requirements.
A good continuous data protection solution for AIX provides true CDP for nearly instantaneous recovery of applications and data at the push of a button. When data is accidentally or maliciously corrupted or deleted, the software should be able to reverse the damage and allow operations to continue normally. This added level of cost-effective data protection makes it an important contributor to any business continuity and disaster recovery strategy.
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