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Today, the editor will show you how to deal with eva storage crashes. The knowledge points in this article are very detailed. Friends who feel helpful can browse the content of the article with the editor, hoping to help more friends who want to solve this problem find the answer to the problem. Follow the editor to learn more about "how to deal with eva storage crash".

Fault description

The user holds a HP EVA 4100 storage, 23 fiber optic hard drives with a capacity of 300G, and the upper layer is mapped to a server with windows system. They begin to find that there are three hard drives with yellow light, and the storage can still be used normally at this time. Then the user begins to contact the operator to replace the hard disk. In the process of replacing the hard disk, another hard disk lights up offline. At this time, the storage crashes and cannot be used. The user tested the four hard drives and found that the heads and disks were damaged in all the four hard drives, and the data could only be recovered from the remaining 19 hard drives.

Second, backup data

Considering the security and reducibility of the data, it is necessary to back up all the source data before data recovery, in case the data cannot be recovered again for other reasons. Mount the disk to a normal backup server as read-only, and use the dd command to mirror all the disks into files.

Third, fault analysis

1. Analysis process

After testing the disk, there are four hard drives with physical failure, all of which are damaged. After the disk is damaged, the data on the hard disk cannot be backed up, so these four hard drives are completely damaged and can no longer be used. Only the remaining 19 hard drives can be used for recovery, because the storage can still be used normally when the previous three hard drives are offline, and the storage crashes when the four hard drives are offline. Therefore, in the case of missing a hard disk to recover, it can be predicted that there will be some missing data.

2. Recovery process

(1) parse the basic information first, and then analyze the header information, as shown below:

(2) parsing RSS group information. RSS group information is important for eva recovery, as shown below:

(3) parse the lun information. After parsing the lun, parse the addressing bitmap information, as shown below:

(4) parse the MAP bitmap information and parse the data. Extract the MAP bitmap information through the lun information. Through the MAP bitmap information, extract the data blocks into logical volumes and parse them, as shown below:

IV. Conclusion of data recovery

User data is due to too much offline storage hard disk storage problems can not be accessed normally, offline hard disk scratches, unable to recover the data of offline hard disk. Based on an understanding of the underlying structure of EVA4100 storage and experience in dealing with similar fault types. And the data needed by the user are all small files, so the whole recovery process is quite smooth. The recovered data has been verified by the user, and the data has been recovered successfully.

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