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

A few days ago, I received a set of 4-disk SCSI RAID0+1 data recovery. The customer said that he had done two sets of raid1, and now the raid status shows that there are 3 fast disk offline. If the two sets of disks are raid1 respectively, there should be a set of logical disks that can work properly now, but this is not the case. I have doubts. What is the reason?

No abnormality was found when the hard disk was separately linked to the SCSI adapter into the system, and there was no obvious raid information area. After comparison, it was found that disks 1 and 3 and disks 2 and 4 had similarities in each group, but there were a lot of inconsistent data behind them. There are partition tables in disk 1 and disk 2, and the description in each partition table indicates that the total partition of the original logical disk is about 68G.

Could it be two groups of RAID0? But No. 1, No. 3 and No. 2 and No. 4 all have exactly the same data, which is not scientific. That is RAID1+0 (that is, do RAID1 in pairs, and then do RAID0, this kind of security level is high, the customer is made by the integrator, the most likely). Within a period of time, one of the two groups of RAID1 has a hard disk offline (after that, it is equivalent to RAID0, and can no longer provide any redundancy). Later, another hard drive went offline and the system crashed. This situation is very consistent with the performance in RAID. It could also be RAID0+1 (that is, do RAID0 in pairs, and then do RAID1, which is not good, and it is unlikely to infer). In this way, except for the RAID composed of 1 and 3, there are no errors, the reorganized data is directly written back to RAID, the system can be started normally, and the file access is also normal.

But there is a problem during the verification, this is the data from two years ago! Is it possible that the user made a RAID0+1 and one of the RAID0 in the RAID1 was offline (it should be 1 or 3), causing the entire RAID0 to go offline (two offline) and then working as a single RAID0 (think of it for more than two years, Khan! Until recently, one of the remaining sets of RAID0 was offline and RAID was completely paralyzed. The raid card used by users is ADAPTEC's 0-channel raid card, which is relatively low-end and cannot safely buffer data. finally, when the data is offline, there is a problem with the consistency of the file system due to reasons such as not being written to the data part.

Reorganize disk 3 and 5, correct the error, and restore the data 100% successfully.

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