Warning: The Number of drives per RAID group value was adjusted to meet the requirement for the minimum number of disks per group for this type of RAID.
|Total usable storage capacity (TB):||0.50 *|
|RAID type:||RAID-DP (stripe set with double parity and two dedicated parity disks)|
|Number of RAID groups:||1|
|Number of drives per RAID group:||3|
|Total number of drives:||3|
|Drive capacity (GB):||500|
|Capacity of a single RAID group (GB):||500|
|Space efficiency:||0.3333 (33.33%)|
|Fault tolerance:||2 disk drives per RAID group|
|Minimum number of drives per RAID-DP group:||3|
|Single drive cost:|
|Cost per TB usable:|
RAID-DP is a double-parity RAID implementation by NetApp. In essence, RAID-DP is RAID 4 with an additional dedicated parity disk storing
so called "diagonal" parity information.
Performance shortcomings of RAID-DP are mitigated by the NetApp proprietary WAFL (Write Anywhere File Layout) file system. WAFL never overwrites existing disk blocks and stores new data using available free space. In addition, WAFL optimizes disk write operations by caching and aggregating incoming write requests in NVRAM first, and then writing data to disks in full stripes.
* Storage reserved for WAFL operations reduces usable capacity provided by the underlying RAID group(s). For more details see NetApp Usable Space Calculator.