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This article introduces you how to recover data from EMC CX4-480 server RAID failure. The content is very detailed. Interested friends can refer to it for reference. I hope it can help you.

[Server Data Recovery Failure Description]

The user's EMC CX4-480 storage server went offline due to a hard drive failure. There are 10 hard drives in the server, 7 of which make up a RAID 5 disk array. The other 3 hard disks are disconnected disks in the process of using the server. The user only adds new hard disks to rebuild when dealing with disconnected disks, and does not unplug the disconnected hard disks. Now there are 3 disconnected disks, so there are 3 redundant hard disks in the server.

The server administrator concluded that the cause of the server crash was a hardware failure in the hard disk in the array, which caused the server to crash, so he handed all the hard disks to the hardware data recovery engineer for physical inspection of the hardware. Hardware data recovery engineer physical inspection of all hard disks in the server one by one and did not find any physical failure of hard disk, so server data recovery engineer had to do a full mirror of all hard disks to analyze the server raid.

Server Data Recovery

After mirroring all disks according to the data recovery process, the server data recovery engineer began to analyze the RAID structure of the server; after analysis, the server data recovery engineer found that the hard disk in the server added an 8-byte check for every 512 bytes, which became 520 bytes per sector. In this way, it will be very difficult to continue the raid structure analysis. In order to improve the work efficiency, the server data recovery engineer wrote a Mini programs to remove the 8-byte check to facilitate the later work.

After all disks have been converted, engineers continue to analyze the RAID structure. Since there are three old disks, you need to eliminate the old disks by comparing each disk, that is, two disks have the same front part, and one of the two disks is old. The old disk has less data than the new disk. There will be 3 pairs of such disks, and all the old disks can be excluded.

Next look at RAID structure, because customers use NTFS file system, with MFT can easily find RAID structure. After knowing the RAID structure, it is found that this is not a normal RAID 5, but a double cycle. Unable to restructure RAID with data recovery tools, had to restructure raid array in other ways! After reorganizing RAID, it was found that the data was not up to date. Server data recovery engineers guess that RAID 5 may have dropped a hard disk first when the administrator did not find it in time, and did not add a new hard disk in time to rebuild. After running for a while, another hard disk dropped, causing the entire RAID to be unavailable. So you also need to find an old disk to generate the latest data. Continue to search for work! Server data recovery engineers use exhaustive and verification methods for analysis, that is, assuming that a disk is offline, kick off the disk and reorganize RAID, but not to generate all the data, but only to generate the first 5G of data, we only need to check whether the bitmap information of this index table is correct. If correct, the RAID reorganization is completed by generating the RAID data

About how to carry out EMC CX4-480 server RAID failure data recovery to share here, I hope the above content can be of some help to you, you can learn more knowledge. If you think the article is good, you can share it so that more people can see it.

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