VIDEOTEKNIKA Engineers explains – What is RAID ?

RAID (originally redundant array of inexpensive disks; now commonly redundant array of independent disks) is a data storage virtualization technology that combines multiple disk drive components into a logical unit for the purposes of data redundancy or performance improvement.

Data is distributed across the drives in one of several ways, referred to as RAID levels, depending on the specific level of redundancy and performance required. The different schemes or architectures are named by the word RAID followed by a number (e.g. RAID 0, RAID 1). Each scheme provides a different balance between the key goals: reliability, availability, performance, and capacity. RAID levels greater than RAID 0 provide protection against unrecoverable (sector) read errors, as well as whole disk failure.

VIDEOTEKNIKA Engineers Explains : What is RAID 0 ?

RAID 0 is the fastest RAID mode since it writes data across all of the volume’s disks. Further, the capacities of each disk are added together for optimal data storage. However, RAID 0 lacks a very important feature for a NAS: data protection. If one disk fails, all data becomes inaccessible. When weighing performance against protection, keep in mind that a NAS’s transfer rates are contingent upon the bandwidth of the network as well as its own hardware. For example, with both LAN ports bonded and connected to a router that supports port aggregation, the NAS cannot exceed 200MB/s. A recommended option is RAID 5, which offers comparable performance, approximately 75% storage capacity of RAID 0 (based upon total available disks and storage capacities), and data protection.

RAID 0

VIDEOTEKNIKA Engineers Explains : What is RAID 1 ?

RAID 1 provides enhanced data security since all data is written to each disk in the volume. If a single disk fails, data remains available on the other disk in the volume. However, due to the time it takes to write data multiple times, performance is reduced. Additionally, RAID 1 will cut disk capacity by 50% or more since each bit of data is stored on all disks in the volume. A standard RAID 1 configuration includes two disks of equal capacity. However, NAS OS allows you to create a RAID 1 volume with up to three disks or, three disks plus a spare. It is also possible to create a RAID 1 volume using a single disk. While such a volume cannot provide any data protection, it is ready for expansion when you add a new disk. Data protection would become available once the second disk is added to the RAID 1 volume.

RAID 1

VIDEOTEKNIKA Engineers Explains : What is RAID 5 ?

RAID 5 writes data across all disks in the volume and a parity block for each data block. If one physical disk fails, the data from the failed disk can be rebuilt onto a replacement disk. No data is lost in the case of a single disk failure, but if a second disk fails before data can be rebuilt to the replacement hard drive, all data in the array will be lost. A minimum of three disks is required to create a RAID 5 volume. RAID 5 offers comparable performance to RAID 0 with the advantage of protecting data.

RAID 5

VIDEOTEKNIKA Engineers Explains : What is RAID 6 ?

RAID 6 writes data across all disks in the volume and two parity blocks for each data block. If one physical disk fails, the data from the failed disk can be rebuilt onto a replacement disk. With two parity blocks per data block, RAID 6 supports up to two disk failures with no data loss. RAID 6 synchronizing from a failed disk is slower than RAID 5 due to the use of double parity. However, it is far less critical due to double-disk security. A minimum of four disks is required to create a RAID 6 volume. RAID 6 offers very good data protection with a slight loss performance compared to RAID 5.

RAID 6

VIDEOTEKNIKA Engineers Explains : What is RAID 10 ?

RAID 10 combines the protection of RAID 1 with the performance of RAID 0. Using four disks as an example, RAID 10 creates two RAID 1 segments, and then combines them into a RAID 0 stripe. With eight disks, the RAID 0 stripe will include four RAID 1 segments. Such configurations offer exceptional data protection, allowing for two disks to fail across two RAID 1 segments. Additionally, RAID 10 writes data at the file level and, due to the RAID 0 stripe, gives users higher performance when managing greater amounts of smaller files. This means a more generous input output per second for data, referred to as IOPS. RAID 10 is a great choice for database managers that need to read and write a multitude of smaller files across the volume’s disks. The impressive IOPS and data protection offered by RAID 10 gives database managers impressive reliability both in keeping files safe and rapid access.

RAID 10