Launched in July 2011, the Promise Pegasus R6 was the first external Thunderbolt device available that could connect to Intel and Apple’s new high-speed interface.
Formerly known as Light Peak, the current incarnation has been developed to work over copper wires – albeit, over very sophisticated cables. The Thunderbolt cable in fact hides several transceiver chips inside its plug, optimising the transmission line for the truly breathtaking speed for which the standard is specified.
With the help of this 10Gbps interface, there should be ample headroom to let a clutch of hard disks reach incredible read/write speeds, using a RAID configuration to stripe data across multiple disks. In the case of Promise RAID drives, this is a hardware rather that software RAID setup, which also bodes well for maximum performance.
Two versions of Promise’s Thunderbolt desktop storage unit are offered – four-bay as the R4 or six-bay as we tested in the Promise Pegasus R6, each removable tray able to accept either the standard 3.5in SATA hard-disk drive, or smaller 2.5in notebook drives.
The latter capability is useful for bleeding-edge professionals who need – and can afford – to equip the Pegasus chassis with blindingly fast SSDs of 2.5in form.
The Pegasus R6 is a neatly finished tower, clad in a steel wrap with plastic fascia, all sprayed in aluminium-coloured paint. The trays pop out easily after depressing a square button on the tray front. A smaller R4 version is available too, with four bays.
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The only data ports are Thunderbolt, two of them to allow the Pegasus to sit within a daisy chain of other Thunderbolt devices. But the single interface type does mean there’s no legacy support for anything but Macs at the moment. An eSATA or even FireWire 800 port could have proved useful as a fallback interface.
Our sample came pre-loaded with six Hitachi Deskstar 7K1000 disks (3.5in SATA 3Gbps, 7200rpm), ready configured as a RAID 5 array. The current state of the art for 3.5in disk technology is 3TB capacity, so up to around 18TB of storage is possible.
Setup in RAID 5 with 1TB disks, you still get a giddy 4.5TB of online storage. RAID 5 is arguably the best arrangement here for three or more disks, typically providing more speed than a single disk alone while also maintaing enough data-redundancy for one disk to fail without losing any net data.
A comprehensive software utility for OS X is included with the Pegasus, with which you can create different RAID options, audit your drives and oversee the whole unit’s operation. It’s a powerful but very neatly arranged piece of software.
In use, the Pegasus remained surprisingly quiet, despite six churning disks and rear-mounted two cooling fans.
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The R6 version of Pegasus is advertised with transfer speeds up to 800MB/s. We were warned by Promise that some Mac benchmark utilities may not reflect the available speed, as they don’t make use of all available threads. Sure enough, Blackmagic DiskSpeedTest showed us speeds up to 586MBps for writes and 537MBps for sequential reads – both still incredibly quick transfer speeds though.
Using Intech QuickBench, we really saw what the Pegasus R6 could do though. Here the unit broke the ceiling with record speeds of 869MBps reads (100MB data), and up to 717MBps writes. Even random read/writes of smaller 1MB data chunks were impressively speedy: 524MBps reads and 480MBps writes.