Data Replay Services

Computer Crime / Digital Discovery / CCTV Image Recovery / Computer Forensics

Rebuilding Broken RAID 5 Servers

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RAID 5 RebuildWith the increase in volumes of digital data throughout the world the number of servers in existence has risen spectacularly in order to cope with demand. Only a few years ago, server and RAID’s were rather uncommon and only found in larger businesses with hundreds of employees. These days RAIDs are often found in NAS home server systems, frequently as RAID 0, RAID 1 or RAID 5 systems. Similarly, RAID and server data recovery services can no longer be seen as activities that happen on an off chance.

A RAID gives you the ability to combine a number of hard disks into one big hard drive. For example combining 10 2TB hard drives will give you a storage capacity of close to 20TB. That’s enough storage space for a home user to store lots of HD films, photos and music. A system this size will typically support a small company as well but of course it depends on the type of data they are storing. Microsoft Office documents tend to be rather small when compared to other types of digital media such a photographs, music and films.

There’s a huge increase in the demand for storage space and files are also very large – any typical HD movie you may download is often several GB in size and home movies you make yourself are also large. It’s the same with music files – a respectable iTunes library can get many gigabytes in size. With music and movies a lot of people choose the stream the content from a local ISP. This saves on using up your valuable hard disk space but is reliant on a decent and quick broadband connection, else you will see the spinning wheel so often noticed when streaming content over the BBC iPlayer service that is telling you that your internet connection just can’t keep up the necessary download speed so that you can watch your programme uninterrupted.

Servers are used to combine several hard disks into a large storage volume or array. Many servers use a configuration that is known as RAID and there are many types of RAID available. Each type has advantages and drawbacks over others. For example the fastest type of RAID is a RAID 0. Data transfer speeds on RAID 0 are extremely quick so it’s often used by video producers and TV producers because their files are large and a fast data throughput is needed when recording, editing and during playback. The downside of RAID 0 is that is has no data redundancy. Data redundancy is a posh way of saying that it only takes a failure of one of the hard disks that make up the RAID 0 and all your data becomes inaccessible. If this happens to you then you will need to contact a RAID data recovery service who should be able to repair the fault on the hard drive and RAID and be able to restore your files to good health.

Another common type of RAID is a RAID 5. This provides good data transfer speeds and has some built in data redundancy too. The data held on a RAID 5 is stored across the hard disks that make up the RAID volume, if one of those hard drives fail the RAID will continue to work without any loss of data at all. If the RAID 5 does loose one of the hard drives due to a fault it’s important that the broken hard drive is swapped out and a working one installed in its place. This is a process known as rebuilding and many RAIDs are clever enough to allow this to happen without having to take the server offline or even power it down. The faulty hard disk is just swapped out and a new one put in – the rebuild is automatic and completed often in a matter of minutes, although the time it takes to rebuild a server does depend on the amount of data it holds. The more data there is stored on it, usually the greater number of hard drives that constitute the RAID set and the longer it takes to rebuild the server.

Rebuilding is usually the method of choice for getting a RAID 5 with a failed drive back up to optimum working levels, but RAID rebuilding can cause a lot of problems. Sometimes the integrity of the data on the RAID server is not rebuilt as it should be ie. it original data contains several corruptions. When a server attempts to rebuild a system using corrupted data the problem is compounded and becomes significantly worse. Basically a problem that existed in one place will now exist in many others, and this happens for every problem that is found on the server during the rebuild process. A server rebuild that has gone wrong is often a worse case scenario for data recovery companies because the rebuild makes restoring the data very difficult and sometimes impossible. Many professional data recovery specialists will advise that server rebuilds are not performed without first checking the integrity of the hard drives in the RAID array and also the integrity of the hard drives themselves.

Written by Betty

November 14th, 2013 at 9:25 am