Criticizing the RAID Administrator or HDD manufacturer’s tool will not result in data recovery in case of RAID 5 failure. The issue can be resolved only when the data is recovered successfully from the faulty drives.
RAID 5 configuration on storage devices maintains a balance between performance and capacity through parity installation. But, parity requires additional disk and extra space for data storage. Due to this reason, every RAID group needs an additional disk for parity information.
If a RAID drive fails, the redundant array of disks can use parity to rebuild the lost data. But, there are instances wherein two or more disks fail, or the RAID configuration has been functioning with one damaged drive for long. In both instances, the RAID efficiency is affected, and in extreme cases, RAID device becomes inaccessible.
Follow the simple steps to recover the data and re-configure the RAID
Analyze: If the RAID configuration has become faulty or inaccessible, analyze the situation and examine the RAID configuration. Analyze what data has become inaccessible? Analyze the RAID Card and if the card does not allow for initiating the process, then stop. Check the faulty disk(s) in RAID with the help of Drive Monitor.
Read the Factory manual: Factory manuals for the RAID card help in understanding the technicality, card-configuration and troubleshooting steps.
Check Backup: Check if the available backup is up-to-date, accessible and in a restorable state. Check the data viability on a separate drive. Test the data backup on that storage array which has nothing to do with the hard drives inside the original failed array. Also, make sure that all the drives are available and in a healthy state, including the one configured for parity.
Avoid faulty Rebuild possibilities: If any of the drives is not available or not read by the RAID card, then the rebuilding process is not successful, as RAID card will again mark the faulty hard drive as inaccessible.
Do not restore the backup on the same drives as available in the inaccessible RAID.
If the Array fails to mount, then do not try to rebuild the array with the same drives for storage redundancy. Unless the array is wholly aligned as per the original configuration, it is possible that the newly rebuilt RAID corrupts the collected data.
Another possibility is that if the faulty disk is sent to the manufacturer and the RAID is built on the repaired drive. This RAID 5 recovery option also results in the degraded disk.
Avoid such configurations which may result in a faulty disk after Raid 5 disk failure.
Checkthe RAID Card and Motherboard: Possibility is that the RAID Drives are not faulty. Instead, the fault is in RAID card or the motherboard. To rule out this probability, send the RAID card for the replacement to the manufacturer and check again. If the RAID card detects the drives, then RAID configuration is probably ok.
Never guess the RAID Configuration: Do not try to guess the RAID including its parity, rotation, stripe, and offset configurations. Incorrect guesses may result in incorrect configuration, and it will be difficult to salvage the repaired File definitions.
Deploy a Data Recovery software: Data recovery software recognizes the disk arrangement, partitions, parity and stripe values, etc. for a RAID configuration. The software also repairs the corrupt data available in disk partitions and acts as a complete data recovery solution for RAID 5 disk failure recovery.
When an organization is considering installing RAID 5 for data redundancy and performance, it should also connect a drive monitor to monitor the drives in the array. Though the manufacturer’s hard drive tool is available, it’s brand specific. Thus a monitoring software for Seagate drive will not monitor a Samsung drive and vice versa. However, such an issue can be resolved by installing a reliable Drive Monitoring Tool.
The absence of a monitoring tool is risky for data maintenance. Faulty drives remain undetected in a RAID configuration, which may result in RAID failure, and the same holds true for RAID 5 configuration also. At this point, the primary concern for a RAID administrator is data recovery, either by using restorable backup or RAID data recovery software. While a backup check may take considerable time thus prolonging the downtime, data recovery software offers a faster solution by rebuilding virtual RAID and recovering the data on a separate drive.
Eric Simson is an Email Platform Consultant and is associated with Stellar Data Recovery from last 6 years. He writes about the latest technology tips and provides custom solutions related to MS Outlook, MS Exchange Server, Office 365, and many other Email Clients & Servers.