How Does RAID Affect Data Recovery?
IOMEGA IX2 RAID 1:
I have an Iomega IX2 server which was working very well until recently. The business has been using the server to record data from the company computers, but suddenly the system has lost or rewritten the usernames and passwords for this computer. I have had to do a forced reinstall of the software for the server in order to allow people access, and when I opened the computer after this reboot, I discovered that a lot of the information on the RAID 1 array connected to the server is lost. Both of the drives seem to be missing data, so I cannot get a clean image from the drives. I have tried to do some data recovery using software tools, but I can only get a few folders, and know that there is a lot more missing.
LINUX SERVER RAID 1:
I am using a server which runs Linux, not sure of the make, and this is connected to a RAID 1 array with a pair of 1TB Seagate drives. When I installed the array, I set up a system to take ‘snapshots’ of the PC backups in order to ensure that the process was working well. One night, the backups suddenly stopped, but the snapshots did not warn me. As soon as I noticed the backup failure, I ran a test program on each of the drives. This appears to show that there is a lot of corruption and bad sectors on each drive, including incorrect counts in directories, orphaned data and free codes. I ran a program to clean up the disks, and restarted the backups. There seemed to be no further problem until I wanted to recover the data, and now I have found that there are many bad sectors throughout the original file, and it seems as though the RAID 1 array has been operating for a long time with this problem, and that data has been copied as corrupt from one side to the other.
How Does RAID Affect Data Recovery?
RAID data recovery is always different from other data recovery methods. If you are not an expert, it’s always better not to perform the recovery yourself. RAID data recovery mainly focuses on rectifying two main types of damage – logical damage and physical damage.
Logical Vs. Physical Damage
Logical damage can be caused most likely by a power outage which occurs during a data write operation. This can cause problems in reading the data, as files have been incorrectly stored. The RAID data recovery option required here must be a software-based one, in which a program analyzes how the data can be arranged correctly.
Physical damage is actual damage caused to the hard drive. RAID data recovery solutions for physical damage are used to replace the minimal amount of data on the disk drive in order to make the data readable again. Another option is to use special programs to collect the remaining data from the drive and then compile the same to a disk image file.
In most cases RAID data recovery is possible with your RAID volumes re-formatted, however it depends on how the volume is re-formatted. A controller level re-format sometimes overwrites only the array information and leaves the original data, or it overwrites every block on every drive in the array which is a longer low-level process. A reformat using the operating system will help you re-establishing the logical volume very quickly.
Preventing Data Loss on a RAID Drive
The main reasons for data loss on a RAID drive are as follows:
Human mistakes such as accidental deletion, format mismatches, etc.
Hard disk corruption –a RAID pattern gets destroyed when a chkdsk tool tries to fix a RAID disk and thus results in data loss.
Partition table corruption –any corruption to the partition table where partition details are stored results in drive inaccessibility.
Converting a file system –any interruption during a file system conversion can result in data loss from the RAID drive.
The Raid Drive Data Recovery Process
The steps in RAID data recovery process include the following:
Evaluate the media for initial determination of the damage type, potential for recovery, and the effort required to recover the data.
Estimate the amount of work involved, the amount of data that can be recovered, what are the actions to be taken, and the cost required to recover the data.
Mirror the available data on the drive to a safe location, if the affected volume is physically functional when received. This step helps to increase the chances for complete recovery and also keeps the original data available for future when an access to the same is required.
Repair any physical damage that is preventing the data from being accessible.
Recover the data using software processes or programs (logical recovery).
Analyze the data that has been recovered is intact and usable by providing a report.
Return the recovered data on device or volume of your choice as soon as possible.
When you opt for RAID data recovery service, it is always recommended to check the pricing structure carefully. In most cases, the cost for RAID data recovery varies widely depending on the type and amount of damage, as well as the time required to recover the data.