Shulou(Shulou.com)06/02 Report--

Disk array two hard disks offline data recovery case 1:

One of the customer's servers caused a hard disk to flash red for unknown reasons, but the server was still running normally and the administrator did not deal with it, and then another hard disk in the server appeared the same alarm and the server crashed. The data recovery engineer does the following for the data recovery process of the disk array (the following operations are risky, please back up before doing so):

1. Start the server, manually enter the management program to check the raid disk array during the server self-test, and find that the status of the hard disk is Failel. Manually reset one of the offline hard drives to the online state and try to restart the server, but the restart failed.

two。 Re-Fail the hard disk, repeat the previous steps to put another hard disk online, start the server, and the server starts successfully.

3. Check whether the database data in the system and the server are running normally, and then use the array configuration tool to manually rebuild the disk after the Failed. After the completion of the rebuild, the server and the raid disk array system will be restored.

Disk array two hard disks offline data recovery case 2:

In this case, the server that requires data recovery is a brand model 2850. There is a set of 6 hard disk raid5 disk array in the server, the hard disk in the array is SCSI hard disk, the single disk capacity is 300g, and the server operating system is linux Redhat4; file system and ext3 file system. During the normal use of the server, two hard drives are offline due to unknown reasons, and the administrator uses the method mentioned in case 1 to force one of the hard drives online. However, after trying to find that the operating system of the server started abnormally, the data could not be recovered by forced online, so we contacted the North Asia data recovery Center for professional server data recovery operation.

The data recovery engineer made a full sector-level backup of the customer server and found that there were a large number of bad tracks in a piece of the hard disk that was not offline in the backup process, probably because the server had not read the bad part of the hard disk yet. so it's not offline.

After the backup work is completed, the raid array structure is analyzed and the raid structure is verified by reorganizing the raid environment, and the damaged structure is modified and archived manually. Finally, the corrected and archived data can be embedded into a normal server array for data verification.

In the server data recovery work, we encountered a large number of raid5 disk array two hard disks offline at the same time. In fact, raid5 array supports redundancy protection when a hard disk is offline. A group of raid5 arrays will not cause the server to be paralyzed when a hard disk is offline, but if two or more hard drives are offline, the server will be paralyzed and cannot go online automatically. As the raid controller has a certain sensitivity, most of the hard disk drop is only caused by power fluctuations, controller bug and other random reasons, so the disconnect disk may not have serious physical failure. This is the case. But at this time, the risk of forced online operation by the administrator is very great, once the online error will cause the controller to produce some irreversible damage to the data, and when the administrator enters the operating system, it will be repaired because the file system is inconsistent, all the hard disk data in the server is inconsistent, and the data recovery is very difficult.

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