I. Introduction to RAID Disk Array
RAID is the abbreviation of Redundant Array of Independent Disks in English, and the Chinese abbreviation is Redundant Array of Independent Disks. RAID is a combination of multiple independent physical hard disks in different ways to form a hard disk group (logical hard disk), thereby providing higher storage performance than a single hard disk and providing data backup technology to form a disk array. The different methods are called RAID levels ( RAID Levels), the commonly used RAID levels are as follows: RAIDO, RAID1, RAID5, RAID6, RAID1+0, etc.
二, RAID 5 disk array
RAID 5 disk array consists of N (N>=3) disks Array, one piece of data produces N-1 strips, and one piece of parity data, N pieces of data are stored cyclically and balancedly on N disks
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N blocks of disk simultaneously read and write, read performance Very high, but due to the issue of the verification mechanism, the write performance is relatively low. The disk is (N-1)/N, which has high reliability and allows one disk to be broken without affecting all data.
Experimental step environment preparation:
1. Prepare more than three and the same size Partition (fd), check whether the mdadm installation package is installed
2. Command:mdadm -C -v /dev/md5 -l5 -n3 /dev/sd[bd]1 -x1 /dev/sde1
3. View the synchronization process Command:cat /proc/mdstat
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4. View disk usage command mdadm -D /dev/md5
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5Execute “mdadm -f /dev/md5 /dev/sdb1” command to unmount the disk to simulate a disk is hung up.
You can see that it is being replaced, sdb1 has expired
6. Usemdadm /dev/md5 / -r /dev/sdb1Remove and put/dev/sde1 mdadm /dev/md5 –add /dev/sdf1added as a hot spare disk
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RAID 5 disk array is composed of N (N>=3) disks, one piece of data Generate N-1 strips, and at the same time there is 1 copy of parity data, N copies of data are stored on N disks in a circular and balanced manner