unRAID Server is a Network Attached Storage server operating system designed to boot from a USB Flash device and specifically designed for digital media storage. It employs a unique RAID technology, close to RAID4, but without striping, which provides for great configuration flexibility:
- Any combination of IDE and SATA hard drives may be used
- All the hard drives do not need to be the same size or speed
- Hard drives not being accessed may be spun down
- Can rebuild any single failed hard drive
True Incremental Storage
Unlike other RAID systems, unRAID Server supports true incremental storage expansion. You can add capacity by adding more hard drives or by upgrading existing hard drives. This is a great way to make use of older, smaller hard drives you might have laying around.
For example, you might start out by installing one or two new high capacity hard drives along with some number of smaller hard drives you already own. Later, you might decide to replace one of the smaller drives, and unRAID Server will restore the data of the smaller drive onto the new drive, and then expand the file system to incorporate the full size of the new drive.
Better Fault Tolerance
Similar to other RAID systems, unRAID Server permits reconstruction of a single failed hard drive. However in the unlikely event of multiple hard drive failures, data loss would be isolated to only those hard drives which failed. In traditional RAID systems, multiple simultaneous hard drive failure results in complete data loss.
- FREE, unRAID Server Basic: Up to 3 drives: 2 data, 1 parity
- $69, ($99 for two), unRAID Server Plus: Up to 7 drives: 5 data, 1 parity, 1 cache
- $119, ($149 for two), unRAID Server Pro: Up to 25 drives: 23 data, 1 parity, 1 cache