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This article will explain in detail how to analyze the differences in RAID0/1 security and how to deal with data security. The content of the article is of high quality, so the editor shares it for you as a reference. I hope you will have a certain understanding of the relevant knowledge after reading this article.

[background of RAID0/1 analysis]

Based on the previous commission from users, Mengsheng wants to try to analyze the security differences of RIAD0/1, hoping to bring help to more friends who need it. The user's device information is as follows:

1. SCSI RAID0+1, composed of 4 pieces of 36G SCSI

2. After communicating with the user, the user shows that he has done two groups of RAID1. After the failure, there are 3 OFFLINE disks in RAID status.

[RAID0/1 data analysis steps]

Connect the hard disk to the SCSI adapter separately and enter the system. The hard disk is normal and can be identified normally. After analysis, there is no obvious RAID information area, and then 4 disks are compared. It is concluded that disks 1, 3 and 2 and 4 have similarities in each group, but there are a lot of inconsistent data behind. 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.

Based on this, it can be judged that there are three situations:

1. Two groups of RAID0, but there are some identical data in No. 1, No. 3, No. 2 and No. 4, which should be excluded.

2. RAID1+0 (that is, do RAID1 in pairs, and then do RAID0, which is a high level of security). After the subsequent monitoring of the hard disk, it is found that one of the two groups of RAID1 is 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.

3. RAID0+1 (that is, do RAID0 in pairs, and then do RAID1, which is not very good, it is unlikely to infer)

According to the analysis, it is found that except for the RAID composed of 1 and 3, there are no errors. Reorganize the data. Write directly back to RAID, the system can be booted normally. File access is also normal. However, the data examined by users found that it was data from a few years ago, not the part currently needed.

[conclusion of RAID0/1 data analysis]

After detailed communication with users again, we learned that users did RAID0+1 early, and as a result, one of the groups of RAID0 in the RAID1 was offline (should be 1 or 3), resulting in the entire RAID0 offline (two offline), and then has been working as a single RAID0. Until recently, a disk in the remaining group of RAID0 was offline and RAID was completely paralyzed. The raid card used by the user is ADAPTEC's 0-channel raid card, which can not safely buffer the data. finally, when the data is offline, there is a problem with the consistency of the file system because the data part is not written. Finally, disk No. 3 and No. 5 are reorganized, the error is corrected, and the data is correct after re-acceptance by the user, so that the data recovery work is completed.

[RAID0/1 Security difference Analysis]

The above case shows the security difference between RAID0+1 and RAID1+0, so let's talk about this part in detail.

1 、 RAID0+1:

The structure is that more than two hard disks (including two) first make stripes (RAID0) to form the same two groups of first-level logic disks. Then mirror two sets of logical disks (RAID1). As shown below:

Redundancy (security) of RAID0+1: whenever a disk goes wrong, its RAID0 will be offline as a whole and can only be supported by the redundancy of the outermost RAID1. In fact, only one disk can be allowed to go wrong, so if there are more than 4 hard disks, the security will actually be much worse.

Utilization: 1Accord 2

Efficiency: both reading and writing can achieve the theoretical bandwidth of Nswab 2 (N is the total number of hard drives).

Implementation: easy, the controller does not need strong processing power, and usually does not need a large buffer.

2 、 RAID1+0:

The structure is that more than two hard disks are first mirrored (RAID1) to form the same two groups or more than two groups of first-level logic disks. Then two groups (or more than two groups) of logical disks are RAID0. As shown below:

RAID1+0 redundancy (security): as long as there is an error in one disk, there will be no problem in its RAID1, so one disk in each group of RAID1 is allowed to go offline. Security: there is only a 2 / 2 chance of two disks being damaged and crashed.

Utilization: 1Accord 2

Efficiency: both reading and writing can achieve the theoretical bandwidth of Nswab 2 (N is the total number of hard drives).

Implementation: easy, the controller does not need strong processing power, and usually does not need a large buffer.

[conclusion of RAID0/1 Security difference Analysis]

From the above analysis, it is obvious that RAID1+0 has a much higher security level than RAID0+1, but other parameters are the same. Therefore, when you need a high level of security, be sure to choose RAID1+0. In fact, RAID0+1 is a flashy structure, and there are few occasions where it can be applied.

On how to analyze the differences in RAID0/1 security and how to deal with data security is shared here, I hope that the above content can be of some help to you, can learn more knowledge. If you think the article is good, you can share it for more people to see.

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