RAIDs (Redundant Array of Inexpensive Disks)

Software or Hardware based RAID?

Hardware RAIDs are more common and and recommended over software based ones.

  1. True hardware RAID controller cards

    • dedicated expansion card (often PCIe) with own onboard processor, I/O processor or RAID-on-Chip, and memory (cache)

    • RAID logic (striping, mirroring, parity calculations) is handled by the RAID onboard processor instead of the host CPU

    • the most reliable form of hardware RAID

  2. Motherboard/onboard Hardware RAID (“Fake RAID”)

    • motherboards that offer RAID support in their BIOS/UEFI settings

    • relies on host CPU for parity calculations

    • offers minimal level of offloading but not as much as a true dedicated controller

  3. External RAID

    • small scale setup that doesn’t offer the full features of an enterprise storage array

    • consolidate multiple disks into a single logical volume or limited number of volumes

    • single server usage or workstation usage

  4. Enterprise Storage Arrays (SAN/NAS)

    • fully featured, highly scalable storage solution

    • provides shared storage across multiple servers or clients

    • offer robust redundancy

RAID 0

  • Data is split (or striped) evenly across all disks, making it suitable for high performance since I/O is spread across multiple disks

  • no redundancy

  • No fault tolerance