Dell EMC PowerVault MD 34XX/38XX Series Storage Arrays Administrator's Guide

PDF

RAID levels

RAID levels determine the way in which data is written to physical disks. Different RAID levels provide different levels of accessibility, consistency, and capacity.

Using multiple physical disks has the following advantages over using a single physical disk:

Placing data on multiple physical disks (striping) allows input/output (I/O) operations to occur simultaneously and improve performance.
Storing redundant data on multiple physical disks using replication or consistency supports reconstruction of lost data if an error occurs, even if that error is the failure of a physical disk.

Each RAID level provides different performance and protection. You must select a RAID level based on the type of application, access, fault tolerance, and data you are storing.

The storage array supports RAID levels 0, 1, 5, 6, and 10. The maximum and minimum number of physical disks that can be used in a disk group depends on the RAID level:

120 (180 with PFK) for RAID 0, 1, and 10
30 for RAID 5 and 6