RAIDS

What is Hardware RAID?

RAID implementation via a hard drive controller (on motherboard or special card), without any OS involvement High performance Configured outside of the OS

What is RAID?

Redundant Array of Independent Disks (note that some versions are not actually redundant). Grouping of hard disk drives into a single virtual volume. Intended to create larger "disk" and also provide fault tolerance and failover protection in many cases. There is software RAID and hardware RAID

What is RAID 1+0?

a stripe of mirrors - "Best of both worlds" - Speed of striping (RAID 0) - Redundancy of mirroring (RAID 1) - Minimum drives: 4

What is RAID 1?

Mirroring - File blocks are duplicate across 2 or more physical drives - Minimum drives: 2 - High redundancy, if drive fails, no data loss, plug in new one and it will be automatically filled - High disk utilization (every file is duplicated, required disk space doubled)

What is RAID 5?

Striping with Parity File blocks are striped across disks, along with a parity block on another drive - Minimum drives: 3 - High redundancy, if drive fails, parity information can be used to rebuild data on new drive - Efficient disk utilization, files aren't duplicated but some extra space used for parity - Can take performance hit due to parity calculation

What is RAID 0?

striping - File blocks striped (split) across 2 or more physical drives - Minimum drives: 2 - High performance, fast writes - Downside: no redundancy, a drive failure breaks the array