Hardware and RAID configuration

This was an Iomega StorCenter ix4-200d NAS with 4x2TB drives. According to the customer, the NAS contained a Linux-based 4-drive RAID 5 volume. There were two main partitions: one to store a shared folder and the other to use as iSCSI storage for a Citrix XenServer.

Problem:

The continuous reboots made the NAS inaccessible. All four drives seemed healthy. Upon reboot the NAS displayed the error message "insufficient disks for RAID5".

Diagnosis:

• Each hard drive was divided into two partitions. The first and small partition formed a mirrored volume holding the NAS operating system. The second and much larger partition formed a RAID 5 holding an XFS volume.
• We performed a RAID analysis to compute the RAID 5 settings (block-size, disk order, parity rotation and starting sector).
• The root folder of the XFS volume was intact.

Solution:

• File Scavenger® was used to reconstruct the RAID 5. The XFS volume was automatically detected by the quick scan and all data was displayed.
• The iSCSI storage was actually a huge 1.95 TB file under the folder \iSCSI.

Result:

This was a complete recovery.