Within a Scale Computing HC cluster all data is written twice to the block storage pool for redundancy (2N). It is equivalent to Network RAID-10, as the two data chunks are placed on separate physical disks of separate physical nodes within the cluster. This protects against 1 disk failure and 1 node failure at the same time, and aggregates the I/O and throughput capabilities of all the individual disks in the cluster (= wide striping).
Once an RSD fails, the system re-mirrors the data using the free space in the HC3 cluster as a hot spare. Because all physical disks contain data, rebuilds are very fast. Scale Computing HC3 is often to detect the deteriorated state of a physical storage device in advance and pro-actively copy data to other devices ahead of an actual failure.
Currently only 1 Replica (2N) can be maintained, as the setting is not configurable for end-users.
Scale Computing, HC3 [HCI]/8.5.3, x86
Disk Failure Protection, Reads/Writes, Data Availability