RAID Backup Procedures from Data Recovery Link - Denver, Colorado

If your RAID has crashed or has gone off line PLEASE READ THIS DOCUMENT OR CONTACT US IMMEDIATELY before you try to force the array back on line! We understand RAID data recovery and can help you understand your best course of action in recovering your critical data. In most instances, bringing a failed RAID array back on-line after it has failed will cause permanent corruption of the data.

When a RAID 5 array fails it is almost always due to a multiple drive failure not just a single drive failure. RAID 5 arrays have a built in redundancy that can withstand one drive in the array failing and can continue to operate in a state known as -critical- and can read and write data while in a critical state. Because of this built in redundancy it takes two drives failing to finally take the RAID array off-line completely.

Having two drives that have failed in a single RAID 5 array leaves a critical question. What drive failed first and how long ago did it fail? If the RAID controller has a -force online- function, as most Dell Perc controllers do, then by forcing the wrong drive on-line you will corrupt the array and the data will be lost and not recoverable. If the first drive to fail happened three weeks ago and the second drive failed today then there is a three week difference in the data between the first failed drive and when the RAID failed completely because of the second failure. If you bring the array back on-line or do a rebuild using the drive that failed three weeks ago then all the data on the RAID 5 array that has been created or modified in the last three weeks will become corrupt and permanently lost. For this reason we recommend never bringing a failed array back on-line until you are sure what hard drive failed first and exclude that drive from the rebuild. At DRL we can look at the data using a hex editor and can determine the drive failure order and recover your data. RAID data recovery is a difficult process at best and even the best of data recovery companies have difficulty performing the task with any ease. Using -off the shelf- or -free data recovery software- is not recommended unless the permanent loss of data would be acceptable and can easily be re-created or restored from backup.

We can help determine when it is ok to rebuild the RAID 5 array or to stop and take backup precautions. If you would like to send DRL your failed RAID 5 array, click our -Online Evaluation Form- and follow the instructions. It is extremely important that you do not try to resolve the problem yourself if the data on the RAID 5 array is important to your company and cannot be re-created or restored from backup. The complete and permanent loss of your data can occur faster then you can press the -are you sure- button.

Please contact DRL or read the -RAID Backup Procedures- link to the right for instructions on how to perform drive by drive backups of each drive in the array before you attempt to recover your RAID 5 array.

Before you do a rebuild on an array that has gone completely off-line shut down (power off) the computer and all drives in the array and do a backup of each hard drive individually using standard off the shelf programs like "WinHex", or "Symantec Ghost" etc. The backup utility you use must perform a FULL sector by sector backup of the drive and not just the file system or you won't get the data you need backed up and your data could be permanently lost. BE CAREFULL WHEN PERFORMING SELF RECOVERY ATTEMPTS ON RAID 5 ARRAYS