DTI Data has over the many years it has been in the RAID data recovery business, developed a method for recovering data that is unique to the company. Data recovery philosophies’ that have been developed from hundreds, even thousands of case studies have made DTI Data a true leader in the data recovery sciences. Although these philosophies and technologies have been applied through the years to aide in the recovery of our client’s data, much of it has been held close to the vest in order to retain a certain market edge. Today, DTI Data will step outside of that mold and explain in layman’s terms what ‘RAID Discovery’ technology entails and how it can be implemented through the use of ‘RAID Sleuth’, DTI Data’s RAID toolset.
‘RAID Discovery’ in and of itself, is a method for taking data samples from RAID images and employing a five pronged approach to RAID data recovery.
In addition, this recovery can be used to help in the recovery of other RAIDs that may have the same type of architecture. In other words, ‘RAID Discovery’ will get smarter the more recoveries it performs. The following is the simple methodology that is used to bring about this technical phenomenon.
- Clean imaging
Drives that makeup the RAID array must be imaged in a manner that is in a synergistic union with the ‘RAID Discovery’ technology. This means that a sector by sector copy is made of the entire drive as an image. If, during the imaging process, read or timeout errors are encountered, then those are mapped and noted and the ‘RAID Discovery’ technology made aware of the discrepancies.
- RAID Architecture
Every RAID server, RAID card, and RAID firmware, has a unique footprint that can be used to aide in the recovery of a RAIDs configuration. As a simple example, most HP RAID fives use delayed parity as a default. In the older RAIDs this was a 512 sector block with a 32 sector block spiral. The more modern HP RAID five uses a larger block and spiral size. That being said the spiral has always been in 16 block increments. ‘RAID Discovery’ has been taught this and uses it in its discovery process.
- File System Integration
Each file system has a unique on disk footprint that can lead to fast and accurate methods for finding components such as, stripe size, offset, and drive order. In addition, using the file system will advance details such as data type, data size, and data location. This used in harmony with the imaging process makes for a better method of discovery.
- High speed engram sorting
Due to the complexities of data placement it is imperative that certain attributes of a raid be stored in such a way as to allow for high speed queries. Indexing methods, as well as data type are used to bring about a quick solution to a raid configuration.
- Interactive verification
Once a raid has been placed through the paces of the ‘RAID Discovery’ sequence a set of familiar data may be presented to the technician in order to help ensure that the current configuration is in fact the most optimal. This data can be presented in many forms including ‘RAID Sleuth’ as well as the DTI Data website.
This description of the ‘RAID Discovery’ technology is admittedly very general and does not go into the idiosyncrasies of data collection, disbursement, and correlation. It does however give a non-whitepaper overview of the technology. DTI Data hopes that this little insight into our in-house technology will help educate many of our fellow IT professionals.
