Linux disk array technical details (ii)--raid 1 creation

I have described in detail in the Linux disk array technology (a) several types of RAID disk arrays, principles and detailed steps for creating RAID 0. Then this document focuses on how to create a RAID 1 technology:

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The steps are as follows:

① partition

We also take a hard disk of different partitions for example, the actual work should be different hard disk.

Specific partitioning step no longer repeat!

After partitioning the results as shown:

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② Creating RAID 1

Mdadm-c-v/dev/md1-l 1-n 2-x 1/DEV/SDC1/DEV/SDC2/DEV/SDC3

Or

Mdadm-c-v/dev/md1-l 1-n 2-x 1/dev/sdc{1,2,3}

Note:-N is followed by 2 because the third hard drive (which is the partition) is a hot spare and not a disk that creates a RAID 1.

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③ partitioning The MD1

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④ Formatting md1

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⑤ Mount use

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OK, to this RAID 1 is a successful creation!

As I said earlier, RAID 1 is the biggest feature of a hot backup, that is, when one of the disks has a problem and does not result in data loss, then I would like to simulate a disk failure:

First, let's take a look at the configuration file/proc/mdstat get the disk array information:

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Comments:

①SDC3[2] (s): where s means spare disk

②[2/2] indicates that two disks in RAID 1 are normal

③active indicates that the array is read and written correctly

Check out the/etc/mdadm.conf configuration file:

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First step: Simulate/DEV/SDC1 as a fault disk

At this point, I started a different machine to see the phenomenon in/proc/mdstat:

The command is: Watch-n 1 cat/proc/mdstat dynamic per second refresh

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Next, the terminal input command

Mdadm-f/DEV/MD1/DEV/SDC1

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And then look at the changes in the content of/proc/mdstat:

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Did you see it? At this point SDC3 has replaced the SDC1 and ensured the integrity of the data.

Step two: Remove the failed disk

Mdadm-r/DEV/MD1/DEV/SDC1

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This article is from the "Brother Hong Linux World" blog, so be sure to keep this source http://zhengkangkang.blog.51cto.com/12015643/1878528

Linux disk array technical details (ii)--raid 1 creation