RAID (Redundant Array of Independent Disks) by its name suggests that it affords protection for your data which, with the exception of a RAID 0 configuration is true. This however, should not be mistaken for giving full protection of your data.
We have seen many RAID servers arrive for data recovery following a failure, where no backup strategy had been employed. The lack of a backup strategy is taking a gamble with your data which could if disaster strikes, lead to data loss and risk the long term future of your company.
Disaster Can Happen in Many Ways
When it comes to enterprise level storage solutions it is easy to only think of a failure occurring to one of the hard disk drives. While disk failures are the most common reason for a failure in a RAID server, other problems can occur to both the hardware or, through external factors, such as fire or flood.
It should also be remembered that very often all the hard disks drives used in a RAID server have been purchased at the same, and then enclosed within the same controlled environment. They will therefore tend to have similar failure rates, such that when one hard disk fails, it is highly likely that another will also fail within the next 24 hour period.
Rebuild After Disk Failure
When a hard disk suffers a failure within a RAID server, the usual procedure is to replace that drive and initiate a rebuild. Although transfer speeds are now higher than ever, due to the average hard disk drive being used in a RAID being over a terabyte, the time to rebuild the data to a new disk is lengthy task.
During this process, the RAID will operate in degraded mode, but should an error be encountered on another drive, it will be unable to complete. If this occurs, which is of increasing concern, the RAID server will take the array offline. Once this happens, data recovery or restoring the data from backups is required.
RAID Server Data Recovery
In many cases the data recovery process from a RAID server may be faster than locating and restoring the data from backups, it is essential to have that option. Should be the failure of the RAID server lead to a severe or total loss of data, it will be your only means of restoring the data, without resorting to the costly process of manually recreating the lost data.