What Makes Drobo Units Special ?
Each Drobo unit is programmed to make the most effective use of any disks inserted into the system.
BeyondRAID’s drive re-ordering feature: – In traditional RAID systems the exact disk order must always be maintained when replacing disks or migrating to a new system. With BeyondRAID the Disk order does not make a difference, which should reduce the amount of risk when rebuilding an array.
Multiple on the fly protection methods: – BeyondRAID allows (whilst in operation the change between single and dual drive redundancy as long as there is sufficient free disk space remaining to allow the change.
BeyondRAID’s Instant expansion feature: – Unlike traditional RAID’s that require a complete rebuild after replacing each individual disk with one of a larger capacity, the BeyondRAID instant expansion feature allows you to replace any disk at any time, this stems from the fact that a BeyondRAID allows the use of different capacity disks. Replacing a single disk allows access to the newly added capacity.
Drobo Beyond-RAID Pros and Cons
Dual drive systems gain no storage benefit: – As you add more disks to a Drobo BeyondRAID system you start to gain the benefits of the newly added capacity but when using a dual disk system this benefit is not seen. As an example if you have a dual disk system containing a 1TB drive and a 3TB drive the resulting available capacity will only be 1TB as the only available dual disk configuration is disk mirroring (RAID 1)
Real world Challenges: – In the case of multiple disks with differing capacities the system will still have to achieve redundancy of the largest capacity disk, i.e. If you have a 5 disk system containing 4 x 500GB disks and a single 2TB disk you will lose 2TB of storage capacity as the system will have to reserve at least 2TB in order to support the failure of the largest disk.