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RAID (redundant arrays of independent/inexpensive disks) offers data security, improved access times or greater storage capacity than a single disk alone (where multiple disks are treated as a single volume), or some combination of all three depending on the configuration:
RAID 0 employs block-level striping which improves access times by splitting files across two disks, but at the cost of redundancy, which is nil. If either drive fails, the entire array is worthless unless an alternative backup is available.
RAID 1 employs mirroring which automatically duplicates data across two disks. Read-access is the same as for RAID 0, but write access is no better than a single disk. However, should either disk fail, the array will continue to function until the faulty drive is replaced, at which point the array is automatically rebuilt.
RAID 2 employs bit-level striping with dedicated parity, similar to RAID 0 but where individual bits are split sequentially rather than splitting sequential blocks. The disks must be perfectly synchronised and a separate parity disk ensures the array can be rebuilt should either striped disk fail. This form of RAID is theoretical and is not used in practice.
RAID 3 employs byte-level striping with dedicated parity similar to RAID 2 (with bytes rather than bits) but while it is not merely theoretical it is not commonly used either.
RAID 4 employs block-level striping with dedicated parity and requires at least three disks. However, the dedicated parity drive can cause bottlenecks which reduce overall performance.
RAID 5 employs block-level striping with distributed parity using three disks. However, performance is reduced upon failure of any one disk, and older configurations are at risk from the so-called RAID 5 write hole, which is potentially disastrous.
RAID 6 employs block-level striping with double distributed parity. The array can continue functioning with up to two drive failures, albeit at reduced performance.
RAID 1+0 (or RAID 10) employs both mirroring and block-level striping and requires a minimum of four disks. Multiple faults on a single mirror can be recovered from, but if any one disk from both mirrors fail, the entire array is lost.
RAID 0+1 is similar to RAID 1+0, but if an entire mirror fails, the entire array is lost.
RAID-5+3 (or RAID 53) employs both mirroring and block-level striping along with with distributed parity.
What else can I help you with?
Why would you need two hard drives?
To increase the physical storage capacity of the computer, or to create redundancy in RAID configurations for data protection.
How can I get an extra hard drive to mimic and copy my computer hard drive in tandem while using my computer?
It's called a "raid" disk controller. Using a raid controller you can connect 2 or more hard drives in a number of different configurations; one being that the drives are "mirrored".
Where can someone purchase Western Digital External Hard Drives?
Someone can purchase Western Digital External Hard Drives from the Amazon website. The Amazon website has multiple sellers offering the hard drive up for sale.
What are the top four brands of 1 TB hard drives?
The top four brands of 1TB Hard Drives are amongst others Western Digital hard drives, Seagate hard drives, Toshiba hard drives, and Hitachi hard drives.
Do external hard drives fit in a pocket?
There are many portable external hard drives which would fit into most standard size pockets.
What drives are installed in internal bays?
Hard disk drives
How are hard drives indentified?
How are Hard drives indentified and what are their functions
Would swapping xbox 360 hard drives give you rrod?
no
What incorrect configurations have similar symptoms hard drive?
some flash drives are recognized by the system as if they were actual hard drives. when the machine boots from usb the system will say, no OS found. please insert bootable media and restart. -romeo t
Are all laptops equipped with 2.5 hard drives?
Mac laptops may likely have solid state drives (not hard drives). Those drives are 2.5" form factor and can be replaced by hard drives.
What is on the house?
Everything is connected to the motherboard. Everything other than hard drives and disc drives would be directly on the motherboard.
Is a hard disk rewritable and able to be used again and again?
Yes, most hard drives are rewritable. SSD drives can be rewritten to less times than conventional drives, but that is still many times. The OS deletes from hard drives and makes new files all the time. If the hard disk was not reusable, then everyone would be buying them more often, and they would be more easily accessible from the outside of the computer.
