RAID stands for Redundant Array of Independent (sometimes Inexpensive) Disks and is often used in large companies where the volume of data that is accessed is greater than any one individual can access. To this end RAID 5 (although with RAID 3) is used to allow for multiple users to access this data across a network setting on a constant basis. Think of, if you will, like twenty people all trying to read a newspaper at the same time. It is physically impossible but with RAID 5 accessing, changing and saving this data is possible by everyone at the same time because the data is split down into ‘stripes’ and saved across all five drives.
Likewise RAID 5 can be set up so that the information can be saved to one drive and then mirrored across the other four for safe keeping.
With RAID 5 all five drives are utilised and it is reminiscent of a jigsaw with pieces (stripes) being assigned to each drive in order to make up the whole. Many more modern RAID 5 devices allow for what is known as ‘hot swapping’; the process whereby a defunct or exhausted hard drive can simply be removed without ‘downing’ the machine and replaced while the RAID device continues working. The new device is then used to back up the data that was made while that particular drive was out of commission.
RAID 5 Rebuild Problems
Here at Belfast Data Recovery we are contacted on a regular basis by companies who operate RAID 5 setups and have had to try and complete a rebuild after a drive has failed; in doing so not only do they risk losing their data (at least a portion of it) but also run the gauntlet when it comes to performing a rebuild. To many the prospect of a rebuild is a daunting one because a hard drive replaced that has not been correctly formatted, does not gel with the others, or has issues communicating with the controller card, will bring the rebuild to a shuddering halt. With this in mind Belfast Data Recovery engineers are often asked if they can be on-site after recovering the data so that they can assist with the rebuild process.
RAID 5 Seek Time/Access Time Issues
All hard drives work with seek and access times and the slower they are the more chance there is that something is wrong with the drive. This is very much the case with RAID 5 and is very noticeable when trying to open and save documents that are stored on a RAID 5 array. If for example a document normally only took a few seconds to open but now takes upwards of a minute one might consider the possibility that there are bad sectors on the drive or that there are problems reading the instructions sent via the controller card. It’s important also to ensure that the format of a newly replaced hard drive in a RAID 5 array is the same as the format of the existing drives.
For more information on issues relating to RAID 5 drives please contact us on 02890 961976 where our engineers will be happy to provide you with assistance, a preliminary diagnosis and a no obligation quote relating to the recovery of data from a RAID 5 array. We may also be able to provide you with on-site assistance when it comes to rebuilding the array after the recovery and replacement of a faulty drive.