raid controller

[BurblingBarbacoa]

what are raid controllers used for? 

[Altecice]

Think of them as a boss  that tells your set of Disks in the array what to do and when to do it. It also organizes the drives "schedules" (read from this set/ write to here)... You get on board RAID controllers that are fine for home use but when you start wanting to control large arrays of disks and expect fast operation you will need a dedicated raid controller(s) for this and to perform other things in the background (deduplication/BitRot protection/Read Cache/Write Cache).

 

How the controller or "boss" organizes your set of disks depends on what you want from them. Here is a good link explaining the basics of the most common drive arrangements: http://www.prepressure.com/library/technology/raid

[Qyoon]

to use your storage device in raid mode.

 

For exemple easy raid are 0 and 1

 

The controller can make the HDD / SSD work together.

 

Raid 0 can combine 2 devices to make one that is faster 

Raid 1 can combine 2 devices to copy the data of a first one on a second one in auto mode.

 

There is tons of different raid and raid controllers or raid cards manage arrays of disk to work in differents modes.

 

This is the basics i guess.