Redundancy is provided by multiple copies (replicas) of the data written synchronously across the cluster. Users set the number of replication copies. We recommend 3 copies as a standard and 2 copies for data that is less critical. This technology is superior to RAID in both reliability and performance:
● Unlike RAID, StorPool replication provides copies on different servers (not copies on one server). So even in the case of a server or component failure you do not lose the data that sits on this server.
● Rebuilding a failed drive/node is done from many drives (and not from one particular drive as in RAID). This means rebuild times are significantly shorter and they do not impact the overall system performance
StorPool also protects data and guarantees data integrity by a 64-bit checksum and a version number for each sector maintained by StorPool.
StorPool provides a very high degree of flexibility in volume management. Unlike other storage technologies, such as RAID or ZFS, StorPool does not rely on device mirroring (pairing drives for redundancy). So every disk that is added to a StorPool cluster adds capacity to the
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cluster, not just for new data but also for existing data. Provided that there are sufficient copies of blocks, drives can be added or taken away with no impact to the storage service. Unlike rigid systems like RAID, StorPool does not impose any strict hierarchical storage structure that links and reflects onto the underlying disks. StorPool simply creates a single pool of storage that utilizes the full capacity and performance of a set of commodity drives.