Install CentOS in Soft/hard RAID

Recently, we have a server that requires RAID. So today we will discuss how to install CentOS to RAID.

There was a lot of nonsense in the front, mainly taking notes for yourself. laruence quickly clicked the upper right corner of the cross.

First, because the motherboard chip is not supported, the cold blog did not successfully install hard RAID. For hard RAID, there are only Windows and some experience.

Please refer to RAID10 here



I. Hard RAID

1.1 hardware settings

First, the motherboard MUST support RAID or add RAID cards. Here, we use the gigabyte MA785GMT motherboard series as an example. First, enable the RAID option in the bios. If it is gray, select the hard disk interface to STAT.

Then, press Ctrl + F to go to the RAID settings page and set RAID 0/1/5/10.

The preceding instructions are described in detail. No driver is found for this board-mounted chip.

1.2 If you check that the RAID settings are correct, start to install CentOS. After the disc is started, install CentOS by default. If you can identify it, it is better.

1.3 If RAID is not identified, but several independent hard disks, reboot the installation disk, enter linux {text} nostrorage, and manually select the driver.

1.4 if the problem cannot be solved in the previous step, go to the chip/motherboard official website to find the corresponding linux driver, and then load it through the soft drive or other methods.

Ii. Soft RAID

If none of the above fails, you can only perform software RAID like a cold blog.

2.1 perform raid 10. If/boot is mounted to the RAID10 partition during custom disk partitioning, a message similar to/boot can only be mounted to raid1. For this problem, the cool-blog's solution is to split/boot first. If RAID 1 is used with another disk and raid 10 is used, it will be messy.

2.2 fortunately, RAID10 is supported for other mount points. The method is as follows, if you do the same for raid1.

For example, there are four hard disks, sda sdb sdc sdd

Partition the same size in sd [a-d] and select RAID as the type.

Click the RAID button to bring up the RAID wizard. Select the second one to select the mount point and select the RAID type.

The above content is for reference only because there is not enough research information. Raid0: Data strip and Data Stripping

Raid1: Image

What is the comparison between RAID10 and RAID01?

RAID10 is to first make a mirror image and then make a strip .?

RAID01 is to first strip the image and then make the image.

For example, if you use six disks as an example, RAID10 divides the disks into three groups of images and then strip the three RAID 1. RAID01 uses three disks as RAID 0, and then uses the other three disks as the mirror image of RAID 0.



The following uses four disks as an example to describe the Security differences:

1. In the case of RAID 10, we assume that when DISK0 is damaged, the entire RAID becomes invalid only when one disk of DISK1 fails in the remaining three disks, we can simply calculate the failure rate to 1/3.

2. In this case, we still assume that DISK0 is damaged and the strip on the Left cannot be read. In the remaining three disks, As long as either DISK2 or DISK3 is damaged, the entire RAID becomes invalid. We can simply calculate the failure rate as 2/3.

Therefore, RAID10 is more secure than RAID01. In terms of the logical location of data storage, under normal circumstances, RAID01 and RAID10 are identical, and each read/write operation produces the same IO quantity, therefore, there is no difference in reading/writing performance between the two. When a disk fails, for example, if DISK0 is damaged, we can also find that the reading performance is different in both cases, the read performance of RAID10 is superior to that of RAID01.