access takes precedence over the rebuild process. If you continue to use the R1 volume during the rebuild, the
rebuild process will take a longer time to complete, and the host data transfer performance will also be affected.
2.1.6 R10 MODE
The R10 MODE storage policy combines the features of both R0 and R1. Performance is provided through the
use of R0 MODE, while adding the fault tolerance of R1. The implementation of R10 requires four drives. The
drives are assigned as two sets of striped pairs. The data is written to R1 set and provides data redundancy.
Alternating blocks of data are then striped (R0) across another R1 set. This provides improved speed. The
resulting storage capacity of the virtual R10 volume will be two times of the smallest drive.
If one drive fails, the R10 volume is still usable, but it is in a vulnerable state because its mirrored hard drive is
inaccessible. When the offline drive comes back online, the appliance begins a rebuild process immediately to
restore data redundancy. A message appears in the LED indicator to notify you that a rebuild is in progress.
Although the volume remains available during the rebuild process, the volume is susceptible to data loss through
damage to the remaining drive until redundancy is restored at the end of the rebuild and verification process. Host
access takes precedence over the rebuild process. If you continue to use the R10 volume during the rebuild, the
rebuild process will take a longer time to complete, and the host data transfer performance will also be affected.
2.1.7 R3 MODE
The R3 MODE storage policy requires a minimum of 3 drives to implement. The R3 MODE adds fault tolerance to
drive striping by including parity information with the data. R3 MODE dedicates the equivalent of one drive for
storing parity stripes. The data and parity information is arranged on the drive array so that parity is written to one
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