Recent questions tagged raid
RAIDs (Redundant Array of Independent Disks) are a technology to increase resilience against disk failures and/or performance by grouping physical devices and presenting them to the operating as one virtual device. RAIDs can be implemented in hardware (using an adapter card) as well as in software (e.g. via
mdadm or ZFS on Linux, or via
diskmgmt.msc on Windows). There are several commonly used RAID levels:
- RAID-0 (also known as stripe-set): Increases performance by distributing data across multiple disks, but decreases failure tolerance because the RAID will fail if at least one member disk fails (for which the chance increases with each added disk).
- RAID-1 (also known as mirror-set): Increases failure tolerance by writing the same data on both member disks, but does not improve performance.
- RAID-10: A RAID-0 of 2 or more RAID-1 sets, increases both failure tolerance and performance at the cost of increased disk count.
- RAID-5: Distributes data across all member disks, but distributes parity information across all member disks as well. The parity data ensures that a single disk failure will not destroy the entire RAID (unlike RAID-0), but management of the parity information also decreases performance compared to RAID-0 or RAID-10. The advantage over RAID-10 is that RAID-5 requires only one additional disk for data redundancy whereas with RAID-10 half the disks store redundant data.
- RAID-6: Similar to RAID-5, but with two parity blocks instead of one.