RAID disk array principle and implementation

RAID: Redundant Arrays of inexpensive disk fault tolerant low-cost RAID array

A number of technologies (software/hardware) that consolidate many small disks into a single large storage device with the ability to protect data and improve storage rates

disk array Benefits :

• Data security, reliability (data rebuild, restore)

• Improve read and write performance

• Increase capacity

Grade category :

RAID-0: The average amount of data is deposited on each disk in equal portions

• Benefits: Highest Performance Storage speed

• Cons: A piece of disk is damaged and data is all lost

RAID-1: Half of the disk as a full backup, image mode (mirror)

• Pros: Security Full backup

• Cons: Half of the disk capacity is used to back up

Raid-10:raid 0+1 or RAID 1+0, requires more than four blocks of hard drive

RAID-5: Comprehensive considerations for performance and backup

• At least three pieces of hard drive

• When the data is written, the same bit check code (parity) is recorded, each time it is recorded on a different disk, because there is parity, so the overall RAID-5 capacity is the number of disks minus one piece.

RAID-6: Similar to RAID-5, using two blocks of capacity to record parity, so you can allow two of disk damage

Spare disk: Prepare disks, auto-replace when a disk is broken

two different types :

Hardware disk array (Hardware RAID): Through the disk array card, performance is good, but high cost

Floppy disk array (software RAID): Software-enabled: mdadm tools under Linux

To Create and delete steps :

1:4 partitions Create a RAID5 array, three blocks used, one as spare disk,

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2: Formatting and mounting

• [Email protected] ~]# MKFS.EXT4/DEV/MD

• [Email protected] ~]# Mkdir/mnt/raid

• [Email protected] ~]# Mount/dev/md0/mnt/raid

3: View disk array information

More information

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View by cat/proc/mdstat file

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4: Subsequent operations

• mdadm--manage /dev/md0 [--add device name] [--remove device name] [--fail device name means that one of the devices is set to error mode]

5: Uninstall close raid

• First Umount

• Mdadm--stop/dev/md0//Note Be sure to turn off the software

This article is from the "Call Me boxin" blog, so be sure to keep this source http://boxinknown.blog.51cto.com/10435935/1663971

RAID disk array principle and implementation