RAID 5 arrays at one time were the preserve of enterprise storage solutions. The price of enterprise level hard disk drives and RAID enclosures has dropped over the last decade to a point where small and medium sized office and even some home users can afford to install a RAID 5 array.
At DiskEng we have a vast array of experience in data recovery from RAID 5 server systems, ranging from a simple three disk RAID through to the largest RAID arrays comprising more than a dozen hard disk drives. RAID data recovery is a complex process requiring an in-depth knowledge of both the file system and the underlying RAID architecture.
Speed with Parity for Safety
In a RAID 5 array the data is striped across the set of drives in order to increase the read/write speed. This gain in performance is offset against the requirement to re-calculate the parity, which is used to provide the redundancy, each time new data is written to the RAID.
The RAID 5 architecture was for many years seen as the perfect compromise between speed and safety. The marketing behind RAID 5 technology was so successful that many users thought that they did not need to implement a backup strategy, which can potentially lead to a loss of data.
Rebuild Using Redundancy
When a single hard drive fails in a RAID 5 array it will continue to operate in degraded mode, using the parity information to generate any missing data. It is inadvisable to allow a RAID 5 to operate in degraded mode with attempting to rebuild the failed drive.
A failed hard drive in a RAID 5 array can be replaced, onto which the data and parity information, can then be rebuilt. This should always be done immediately, as the failure of a second drive would take the RAID array off-line, with data recovery the only option available.
The latest high capacity hard drives containing terabytes it will take much longer to rebuild a RAID array than it a decade ago, despite the increase in data transfer speed. The risk of a further failure occurring during the rebuild is therefore greatly increase, making it wise to plan an alternate backup strategy while this process is taking place to guard against data recovery being required.
RAID 5 Data Recovery
Should more than one disk in a RAID 5 array fail, or the RAID controller suffer a failure, you will need to seek professional help from RAID data recovery specialists such as DiskEng, who have an in-depth understanding of both the file system and the underlying RAID architecture.
When a RAID array fails it is important to make the right decision, as the security of your data is of the utmost importance. Making the wrong choice could have serious consequences, risking the loss of your data and possible putting future of your company at risk.