Best answer: Redundant Array of Independent/Inexpensive Disks (RAID) is a technology that allows storing data across multiple hard drives. The purpose of RAID is to achieve data redundancy to reduce data loss and, in a lot of cases, improve performance. The best way to get in on the RAID action is with a NAS.
Redundant Array of Independent Disks
Redundant Array of Independent Disks (RAID) is a virtual disk technology that combines multiple physical drives into one unit.
The most common types are RAID 0 (striping), RAID 1 (mirroring) and its variants, RAID 5 (distributed parity), and RAID 6 (dual parity). Multiple RAID levels can also be combined or nested, for instance RAID 10 (striping of mirrors) or RAID 01 (mirroring stripe sets).
What is RAID and what are the different RAID modes?
|RAID 0||Striped disks|
|RAID 1||Mirrored disks|
|RAID 3||Striped set with dedicated parity|
|RAID 5||Striped disks with distributed parity|
The best RAID configuration for your storage system will depend on whether you value speed, data redundancy or both. If you value speed most of all, choose RAID 0. If you value data redundancy most of all, remember that the following drive configurations are fault-tolerant: RAID 1, RAID 5, RAID 6 and RAID 10.
One area where RAID 5 scores over RAID 10 is in storage efficiency. Since RAID 5 uses parity information, it stores data more efficiently and, in fact, offers a good balance between storage efficiency, performance, and security. RAID 10, on the other hand, requires more disks and is expensive to implement.
RAID 10 is the safest of all choices, it is fast and safe. The obvious downsides are that RAID 10 has less storage capacity from the same disks and is more costly on the basis of capacity. It must be mentioned that RAID 10 can only utilize an even number of disks as disks are added in pairs.
Since everything is mirrored (duplicated), four 2TB disks in RAID 10 give you a total capacity of 4TB of usable space.
RAID 0 is the only RAID type without fault tolerance. It is also by far the fastest RAID type. RAID 0 works by using striping, which disperses system data blocks across several different disks.
RAID allows you to weather the failure of one or more drives without data loss and, in many cases, without any downtime. RAID is also useful if you are having disk IO issues, where applications are waiting on the disk to perform tasks.
When you want to recover your data quickly, RAID 5 is a faster option than RAID 6, as the latter can take a long time to reconstruct the data because of double parity. However, if you don't mind the extra time but want better fault tolerance, go for RAID 6.
Depending on the location of the drives, a RAID 10 configuration can recover from multiple drive failures while using the same percentage of data drives as RAID 1. It can also provide increased performance due to the increased number of spindles in the RAID group.
When you want to store critical and sensitive data, RAID 1 is your best bet as it mirrors data on two disks, so even if there is a problem with the primary disk, you can always retrieve the content from the second one. In general, RAID 1 is a good choice if data redundancy is a key feature of your storage needs.
RAID levels comparison chart
|RAID 0||RAID 10|
|Disk space overhead||None||50%|
|Hardware cost||Cheap||High (disks)|
If you are into gaming and video editing, RAID 0 is the right configuration for your data storage needs. RAID 0 is a standard RAID configuration, which uses striping method to store data on the disk array. It's the most affordable RAID configuration that requires at least two disks.
RAID 0 provides a performance boost by dividing data into blocks and spreading them across multiple drives using what is called disk striping. By spreading data across multiple drives, it means multiple disks can access the file, resulting in faster read/write speeds.
4x SAS 500GB hard drives in a RAID-5 configuration = $1200 ($300 per drive)