Disk Format RAID Introduction

RAID Mode Introduction

The Orico 3559RUS3 HDD enclosure provides five types of disk array build modes, including RAID 0, Raid 1/10, RAID 3, RAID5, Combine, which have different functions, as explained below.

RAID, the English "Redundant Array of independent Disks" abbreviation, the Chinese name is called "Redundant Array of independent disks", referred to as "disk array". (see Wikipedia)

Combine:

Combine mode, in fact, we are familiar with the JBOD (Just a Bunch of Disks) mode, the Chinese name is called "Disk Cluster", in simple terms, or the combination of multiple disk space into a large logical disk, the mode does not have a fault redundancy mechanism.

Combine mode can use two or more hard disk, hard disk capacity is not limited, different capacity of hard disk, combine mode is the total capacity of the hard disk, such as the use of 1TB, 2TB, 3TB each hard disk, after the completion of its usable capacity is 1TB+2TB+3TB It's =6TB.

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JBOD, RIAD 0, RAID 1

RAID 0:

RAID 0 is the combination of multiple disks together into a large disk, without data redundancy, because it spread the continuous data across multiple disk access, so in the Riad mode has the fastest read and write speed, but the security is the worst one, as long as any one hard disk problem, Will cause the entire RAID storage system data to crash and is not recommended for mass storage.

RIAD 0 mode and Combine/jbod look very similar, in fact, the mode of operation is very different, RAID 0 mode of the hard disk is parallel, that is, multiple hard disk work simultaneously, and combine/jbod mode of the hard disk is serial, The second hard disk is written only when the first hard disk is full.

RAID 1:

RAID 1 Mode is the two sets of n hard drives mirror each other, the actual capacity of the hard disk is equal to the capacity of the smaller hard disk, storage speed is slightly lower than a single hard drive, but the security is very good, unless the primary disk with the same data and mirror damage, otherwise, as long as a disk normal operation, the highest reliability.

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RAID 3 vs RAID 3

RAID 3:

Riaid 3 mode uses the Bit-interleaving (data interleaved storage) technology, which needs to be encoded and then partition the data bit after the hard disk, and the same bit after the check of a separate hard disk, but because the data within the bits scattered on different hard disks, So even if you want to read a small piece of data, all the hard drives may be required to work, so this specification is more suitable for reading large amounts of data.

RAID 5:

RAID 5 is a storage solution that combines storage performance, data security, and storage costs, using disk Striping (hard disk partitioning) technology.

RAID 5 requires at least three disks, which do not back up the stored data, but instead store the data and the corresponding parity information on each disk that makes up the RAID5, and the parity information and the corresponding data are stored on separate disks. When one of RAID5 's disk data is damaged, it can recover the corrupted data using the remaining data and the corresponding parity information.

RAID 5 can be understood as a compromise between RAID 0 and RAID 1. RAID 5 provides data security for the system, but with a lower level of protection than mirroring and higher disk space utilization than mirroring.

RAID 5 has a similar data read speed as RAID 0, just because a bit more parity information, the speed of writing data is quite slow, if the use of "write-back cache" can improve performance. And because multiple data corresponds to one parity message, RAID 5 has a higher disk space utilization than RAID 1 and is relatively inexpensive to store.

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RAID 0+1 and RAID 1+0

RAID 1+0:

Raid 1+0 is the first mirror-and-partition data, then divides all the drives into two groups, considered as the lowest combination of RAID 0, and then each of the two groups as RAID 1 operation.

RAID 0+1:

RAID 0+1 is the reverse of the raid 1+0 program, which partitions and then mirrors the data into two groups of hard disks. It divides all the hard drives into two groups, becoming the lowest combination of RAID 1, while the two groups of hard disks are considered RAID 0 respectively.

In performance, RAID 0+1 has faster read and write speeds than raid 1+0. Reliability, when a raid 1+0 has a hard drive that is damaged, the remaining three drives will continue to function. Raid 0+1 as long as one hard drive is damaged, the other hard drive of the same RAID 0 will also stop functioning, leaving only two hard drives operating with less reliability. As a result, RAID 10 is much more common than raid 01, and most retail motherboards support RAID 0/1/5/10, but raid 01 is not supported.

The Orico 3559rus3 external disk array box supports RAID 1+0 and does not support raid 0+1.

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Disk Format RAID Introduction