RAID Data Recovery & Server Recovery

Losing access to the data on your RAID array can happen for a number of reasons. However there are two distinct categories of data loss that will require RAID data recovery services.

1. LOGICAL OR SOFTWARE ISSUES - All of the hard disk drives that make up the RAID array are functioning properly. The RAID data cannot be accessed because of damage to the file system. The operating system whether Linux, MAC or Windows, uses the file system to locate the data on the RAID array. One can think of the file system as a large index containing the location and order of all the parts of data that make up a particular file. Examples of file system damage on RAID arrays include:

   Accidental deletion	Incomplete Rebuild	RAID initialized reformatted
   Accidental Format or FDISK	Malfunctioning controller	RAID missing drives
   Array incomplete	Master Boot Record bad	RAID Parity error
   Blue Screen of Death	MFT Master File Table damage	RAID rebuild error
   Created New Volumes	Missing RAID partition	Use of Chkdsk or Utilities
   Improper shutdown	Power Interruption Surge	Re-configured RAID
   RAID configuration error	NTLDR is missing	RAID configuration lost
   Replaced wrong drive	Virus Infection	Volume Reconstruction Error

   
    
2. PHYSICAL ISSUES - One or more of the hard drives in your server, RAID box, SAN or NAS are NOT functioning properly. RAID5 is created to allow the failure of one hard drive with no loss of data. However, the failure of one drive can cause the RAID to start rebuilding itself and if another hard drive in the array fails even momentarily during this process, data can become inaccessible. Hard disk drives may become defective for a variety of reasons as outlined in the hard disk drive recovery section.

RAID Data Recovery from a single drive server or a multiple drive RAID 5 array is initially treated much like any other recovery. Memofix's first step is to secure exact images or mirrors of all the storage devices. We may need to repair a defective or crashing hard drive in order to get an image. If it is a single hard drive we would then use our standard analysis and RAID data recovery techniques to repair any logical damage. In most cases we do not have, nor need your RAID box or controller. Once images have been secured, we analyze the entire set of RAID drives to determine the original stripe size, block size, and striping scheme. By calculating and scanning the parity across the entire RAID array we can identify the integrity or degradation of any RAID stripe or slice. We then assess any damage in relation to the original installation and attempt to segregate or repair the effects of that damage. Then using specialized RAID utilities, we attempt to mount the RAID volumes virtually and repair any damaged file system structures that may be preventing us from accessing the data. In other cases where the damage is more severe we may choose to de-stripe the RAID to another storage device. Either way, Memofix should then be able to access the damaged volumes and use our standard recovery techniques to salvage the data.

• In the cases of a multiple drive RAID array with parity or redundancy built in, there is another option available if one of the drives becomes inaccessible or corrupted. We can simply use the data from the remaining good drives to recreate the data off the one inaccessible drive. However, a good RAID implementation should have already informed you of any drive failure and seamlessly continued to operate by recreating the missing data on the fly. In most instance RAIDs we see for recovery are in much worse shape.
• We see cases where one drive of the RAID array failed 4 months previous. The defective hard drive was NOT replaced and the RAID continued to operate in a degraded mode until a 2nd hard disk failed. At this point the RAID now has 2 bad drives which render it totally inaccessible.
• We also see a lot of RAID cases where a single disk drive failed and the operator installed a new drive in its place and rebuilt the array from scratch.
• Or we see RAIDs where a new drive was installed in the wrong slot and when the RAID attempted to rebuild, it corrupted itself.

We see such an enormous variety of damage that was caused after the initial failure and by the user's recovery attempts, that we must stress the same advice, time after time; if your data is life and death, do nothing after discovering a data loss and send it to the RAID data recovery specialists!