HDD - Getting More Bandwidth

• The first thing was getting more throughput (or bandwidth)
• This was achieved by combining disks in groups.
• This is usually done by using disk striping
• which is the simplest form of RAID (RAID 0)
• If 1 disk = 100MB/second, 10 disks = 1GB/second.
• With many disks - the chance of a failure increase
• Thus protection schemes were formed:
  • Mirroring - RAID 1 - no performance penalty.
  • parity protection - RAID 4 - parity (re)calculations slow down writes.
  • Alternating Parity protection - RAID 5
  • dual-failure parity protection - RAID 6.
  • Combining mirroring with striping - RAID 10.

Originally written by guy keren