RAID allows the combination of multiple hard drives into a single large volume. This is for redundancy and performance factors. RAID is mostly used to prevent the loss of that data during hard drive failures, but can also be used if you want to improve performance on your hard drives within a server.
Redundant Array of Independent Disks (RAID) allows the combination of multiple hard drives into a single large volume. This is for redundancy and performance factors. RAID is incredibly useful is you want to have large quantities of data and prevent the loss of that data during hard drive failures, but it can also be great for if you have high disk usage and want to improve performance on your hard drives within the server.
RAID comes in two different types, hardware, and software.
The hardware version of RAID uses a controller that sorts and manages all disk drives within an array, which by turn helps to increase the performance rates for that array by offloading any processing power to a dedicated piece of hardware.
As for the software version of RAID, it draws the processing power from the server and uses them to manage the disk arrays, which can impact the performance of the drives if there aren’t enough resources available to draw processing power from, but it does still provide redundancy like the hardware version of RAID does, just not the same performance improvements.
There are multiple levels of RAID, 7 types to be exact: RAID0, 1, 5, 6, 10, 50, and 60.
RAID 0 is mostly for performance benefits, because it stripes data across all drives in order to combine their read/write speeds within the array, allowing you to have all of the full capacity of those drives; this means that you don’t get any protection if a drive failure ever occurs, especially because if even one drive within an array fails, it means that all of the data will be completely lost.
RAID 1 is used to store all data on each disk drive, and does not improve the performance, but due to its mirroring, it is better used for the intention of data loss and drive failures.
RAID 5 also stripes data like RAID 0 does but does it across a minimum of 3 different disk drives and writes parity data onto all of the drives which can allow it to rebuild a drive within an array if there were any drive failures to occur. However, the more disk drives that you add, the more space on the disk is lost, and additional to that it can only handle one drive failure, if any more disk drives fail then all data will be lost.
RAID 6 can stripe data across a minimum of 4 hard drives and writes with double parity data. Unlike RAID 5, this level can handle two disk drive failures without losing any data, but anymore and you will lose data. With RAID 6 you can gain the combined read speed for all drives within the array and gain a slight increase in write speed. However, you will lose out on more capacity than RAID 5.
RAID 10 is like a combination of RAID levels 0 and 1 and requires a minimum of 4 hard drives. All of the read/write speeds are combined from the array in this level, and RAID 10 is able to handle approximately half of the drives within an array failing without losing data. This level is preferred for its improvement in read/write speeds in smaller arrays compared to RAID 5 or 6.
RAID 50 uses a combination of 2 or more levels of RAID 5swith a RAID 0. It stripes all of the data across the multiple RAID 5s which allows for a combination of read speeds for all drives within an array, and also the combined write speeds from the individual RAID 6s. RAID 50 allows 1drive in each RAID 5 have a disk drive failure without the loss of data.
RAID 60 combines 2 or more levels of RAID 6s with a RAID 0,similar to RAID 50. All of the data is striped from across the RAID 6s allowing the combined read speeds of all the drives within the array as well as the combination of the write speeds from all of the individual RAID 6s, which means that you can have 2 drives from each RAID 6 fail without losing any data.
If you’re trying to decide whether to choose hardware or software RAID, you should consider a couple of things, such as what drives you have in your server. For instance, NVMe drives aren’t always compatible with hardware RAID due to their high-speed rates, because hardware RAID cannot keep up with it, but by going with software RAID you can make it work alongside your NVMe drives.
Hardware RAID uses controllers and RAID cards to manage the RAID configurations separately to the OS and doesn’t take away any processing power from the disk drives that it is managing. Which allows it to free up more space and increases speed for read/write data, and it can work on any OS, when a drive fails you can just take it out and plug in a new one.
But, it is more costly than the software version of RAID, and if the controller fails then you have to fine a new one that’s compatible to make sure it preforms the same way that you set it up to work in.
As for Software RAID, it uses up the processing power of the OS where the disks are installed and allows the user to configure all of the arrays without being restricted by the controller you have with hardware RAID. Plus, the price is cheaper than the hardware version of RAID.
However, software RAID is usually slower than the hardware version because of the usage of processing power for the software. Read/write and operation speeds can be slowed down as a result. This version of RAID is also typically specific to the OS that is being used on the server and cannot be used for any partitions shared between OS. Switching out a failed disk with software RAID is also a little bit more complex as you have to instruct the system to stop using the failed disk before removing it from the array and replacing it.