Skip to main content

RAID

Updated Jan 30, 2024 ·

RAID (Redundant Array of Independent Disks) combines multiple physical disks into a single logical unit to improve performance, reliability, and data redundancy.

RAID Classifications​

There are multiple ways to setup RAID disks, depending on the level of resilience that we will want to aim for.

Failure-resistant

  • Systems designed to withstand certain hardware malfunctions without losing data.
  • Achieved through redundancy of storage devices by mirroring the data.
  • RAID 1 and RAID 10.

Fault-resistant

  • Designed for continued operation in the event of hardware failure without any downtime.
  • Quickly rebuild any lost data from the remaining healthy storage devices.
  • Achieve through mirroring or striping with parity.
  • RAID 1, RAID 5, RAID 6, and RAID 10.

Disaster-resistant

  • Broader level of protection from catastrophic events.
  • Utilize two independent zones that always have full access to all the data.
  • RAID 1 and RAID 10, "full mirrors".

RAID 0​

  • "Striping"

  • Stripes data across multiple disks for higher performance but no redundancy.

  • Faster read and write speeds; data is split across multiple drives.

  • Focus is performance, but no fault tolerance.

RAID 1​

  • "Mirroring"

  • Mirrors data across two disks for redundancy .

  • One disk can fail without data loss.

RAID 5​

  • "Striping with parity"

  • Stripes data and parity information across three or more disks.

  • Balances performance and redundancy.

  • In case of failed disk, there will be slower speed in retrieving.

  • Slower speed because its calculating the missing data on the fly.

  • Can only lose one storage device, if more than that, it'll be difficult to rebuild missing data.

RAID 6​

  • "Striping with double parity"

  • Similar to RAID 5 but with additional parity, allowing two disks to fail.

  • Uses two identical pieces of parity data.

  • Requires at least four storage devices.

  • Can lose two disks and still be able to rebuild the data without suffering downtime.

RAID 10​

  • Combines mirroring and striping for high performance and redundancy

  • Requires at least four disks.

  • Faster speed because of the striping of data across two arrays.

  • Can lose two disks and still be able to rebuild the data without any downtime, as long as they're not in the same RAID 1 array.