RAID 5 Rebuild

Degraded RAID 5

A degraded RAID 5 presents as a system that is unresponsive or whose transaction processing times have become unacceptably protracted and noticeable to its clients. The most common example of a degraded RAID 5 is one with a single failed hard disk drive. When a hard drive fails, the system undertakes an automatic rebuild process. This RAID rebuild process then involves reconstructing data on a hot spare hard drive from algorithms and parity references stored across all the remaining working hard drives. These algorithms or processes take preference over client services. During this time the RAID will present to the client user as unresponsive or in technical parlance “degraded.” Once this rebuild process has completed successfully the RAID System will return to a reasonable and responsive working state.

RAID 5 Failed Hard Disk Drive Replacement

. The condition and health of the hard disk drives in a RAID 5 array need to be monitored on a regular basis. There are a number of maintenance applications available to technicians that facilitate comprehensive monitoring and management, the use of which is outside the scope of this blog. Once a failed hard drive is flagged by a RAID system it needs to be replaced with a new healthy hard drive of compatible capacity and performance. The replacement operation needs to be undertaken as soon as is practicable in order to militate against a possible consecutive drive failure and a catastrophic system failure.

RAID 5 Failure Technical Support.

A RAID 5 operating normally is unlikely to fail as a result of simultaneous hardware failure. If all drives were healthy prior to the RAID 5 fail then it is more than likely to be as a consequence of corrupt RAID 5 configuration tables in the control software. With this type of problem you are more than likely going to need the assistance of a technician familiar with RAID 5 set-up and operation and who is able to restore access to your data files. RAID recovery technicians are specialists in their field and their services are unlikely to be at the lower end of your budget, particularly if you need their immediate and undivided attention. Faced with time consuming and unexpected expense, the first thing to do is to adequately prepare the system for diagnosis and data recovery such that you will be making the most efficient use of the time the technician spends addressing your problem.  

RAID System Power Down.

This maybe obvious but it is worth amplifying i.e. the system configuration that you are running your RAID hard disk drives with, is now corrupt or has the potential to become corrupt. Whilst the RAID is in this state it will be abortively trying to rebuild itself and potentially allocating data to areas of the system containing files you would not want to lose. So the first thing to do is to power your system down.

Identify RAID hard disk order.

Once powered down the next thing to do is to record the physical order of the hard disks in the array. You can read a hard drives numeral value from the disk itself however this requires a specialist procedure best left to the technician.

RAID 5 Rebuild.

To rebuild a RAID 5 following multiple hard drive failure or corrupt configuration table is better attended to in a laboratory environment. Here technicians have access to specialist tools, workshops facilities and resources essential to undertaking the rebuild and recovery process. Need help then call our RAID 5 data recovery service.