[data recovery in North Asia] a data recovery case of raid crash caused by hard disk drop during data synchronization of hot spare disk of RAID5 disk array

 

Environmental Science ：

15 It's made up of two hard disks raid5 array ;
raid5 The array superstructure is a xfs Bare partition , The starting position is 0 A sector .

fault ：

One of the hard disks in the array fails and is disconnected , When the hot spare goes online to synchronize data, another hard disk goes offline , Cause interruption of data synchronization process , Array crash , Data loss . The administrator contacted the North Asia Data Recovery Center for help .

Hard disk physical fault detection ：

North Asia data recovery engineers have performed physical fault detection on all hard disks in this array , It is found that the first offline hard disk has found a large number of bad tracks , Later, there were a few bad tracks in the hard disk that was disconnected during data synchronization , To ensure the final integrity of data recovery , Physical fault detection is also carried out one by one for the hard disks that are not disconnected in the array , Finally, it is determined that there is no physical failure in other hard disks .

Data recovery process ：

This is a very typical raid5 The disk array is in the process of hot spare disk synchronization , The hard disk is disconnected raid Collapse cases . In this case , The most convenient way to recover data is to repair the physical failure of the second offline hard disk , Recover the data from the hard disk , Then regroup raid Array is enough .

1、 The data recovery engineer of North Asia has made a read-only backup of all normal hard disks , Backup the second offline hard disk separately , Skip bad sectors in the process , Backup all data as completely as possible . Because there are bad sectors in this hard disk , This part of the data cannot be read , The underlying data can only be viewed manually by the North Asia data recovery engineer , Calculate the data of bad sector position according to the XOR law , Write manually .

2、 After mirroring all the data in the hard disk , North Asia data recovery engineer conducts virtual riad Environmental restructuring , verification riad5 Whether the structure is correct . Replace the first hard disk with the second offline hard disk , Data synchronization .

Verify recovery data ：

After data synchronization , The correctness of the data is verified by the North Asia data recovery engineer , After verification, the administrator will perform the final data verification , After verification , The recovered data directory structure is complete , All data available , The program has no error and runs normally , Finally, it is confirmed that the data recovery is successful .

Tips: ：

In various data recovery cases of the North Asia Data Recovery Center ,raid5 Data recovery cases are common recovery cases . North Asia data recovery engineer found ： because raid5 Redundancy mechanism of array , Users trust too much raid5 Array security , Ignoring the usual maintenance , Eventually, the hard disk in the array is offline , Data loss .

Raid5 Disk arrays are relatively more secure than other types of arrays , But there is still data loss . Don't take it lightly at ordinary times , Regular maintenance 、 Timely maintenance 、 Replace the old and unstable hard disk , In order to avoid data loss caused by hard disk failure as far as possible .