Linux storage experiment 2: RAID operations

Linux storage experiment 2: RAID operating Linux storage experiment 1: creating a file system on a hard disk... Linux storage experiment 2: RAID operations

Linux storage experiment 1: creating a file system http://www.2cto.com/ OS /201303/194226.html on a hard disk
The basic knowledge part is not detailed design, in short several common patterns: raid0, raid1, raid0-1 or raid1-0, raid5 different models between the most desired goal is different, its storage efficiency and security are also different. (1) create RAID www.2cto.com Step 1: Create 5 10 mb scsi hard disks Setting-> hard disk-> add... fdisk/dev/sdb: the partition is/dev/sdb {5, 6, 7, 8, 9}. all of these are logical partitions. Step 2: creating Raid 5 + 1 hotspare raid with four hard disks requires at least three devices mdadm -- create -- auto = yes/dev/md0 -- level = 5 -- Raid-devices = 4 -- spare-device = 1/dev/sdb {5, 6,, 9} then our RAID 5 was built. one hot backup disk will be automatically replaced if it is damaged in the future. In addition,/dev/md0 is our raid5 code. in the future, all operations will be replaced by/dev/md0. Step 3: view the composition of RAID mdadm -- detail/dev/md0: the information shown above is displayed. four partitions are used for raid and one is used for spare device. Step 4: create a file system mkfs-t ext3/etc/md0 on a RAID device Step 5: mount and perform a read/write test mkdir/mnt/raid mount/dev/md0/mnt/raid Step 6: import the definition of the RAID device to/etc/mdadm. conf to enable the RAID device to take effect after each restart. configuration file:/etc/mdadm. conf, you need to know that UUID obtained UUID: mdadm -- detail/dev/md0 | grep-I UUID write format: ARRAY/dev/md0 UUID = UUID step obtained by the preceding query Step 7: set automatic mounting vi/etc/fstab write:/dev/md0/mnt/raid ext3 defaults 1 2 umount/mnt/raid mount-a Step 8: Restart the OS, view RAID information (2) hot backup disk Step 1: Mount and perform continuous read/write operations before mounting. Cp-a/etc // var/log // mnt/raid Step 2: run the following command to simulate the damage of a hard disk in RAID: mdadm -- manage/dev/md0 -- fail/dev/sdb8 mdadm -- detail/dev/md0: 1. if one device breaks down and the device is/dev/sdb8 is displayed below, the/dev/sdb9 used as the hot backup disk (spare device) will automatically replace the broken disk, continue to use. Step 3: Use commands to simulate a damaged hard disk as a hot backup disk and add it to RAID. here, we add the/dev/sdb1 (the primary partition) to the RAID disk as a hot backup disk, remove/dev/sdb8 mdadm -- manage/dev/md0 -- add/dev/sdb1 -- remove/dev/sdb8 mdadm -- detail/dev/md0, /dev/sdb0 is used as a hot backup disk. now Failed Devices is 0. Step 4: Check the RAID composition ....