Review: Promise Technology Pegasus R6 Direct Attached Storage

Promise gives Mac users premier storage kit

Promise Technology's Pegasus R6 direct attached storage (DAS) system uses 10Gbit/s Thunderbolt connectivity, so it will be of interest to Mac users thirsty for more personal storage, or to firms deploying Mac desktops who need fast storage for those Macs.

Priced at $1,499 (£970), you pay a premium for having Thunderbolt connectivity. The standard 6TB Promise SmartStor NS6700, which has dual gigabit EThernet ports, is around £250 less.

To use the Pegasus R6 system, users will need Mac hardware with a Thunderbolt connection, since the Pegasus R6 has no other connectivity, apart from a management serial port [see picture].

The Pegasus R6 we reviewed used Hitachi serial ATA (SATA) 3GB/s Deskstar 7K1000 HDS72101 1TB 7,200 hard disks, which can be set up to a variety of redundant array of independent disk (RAID) configurations [see picture].

In use
First, we installed the Promise Pegasus R6 management utility on our review MacBook Air. We fired up the utility to check what configuration the disks currently had [see picture].

The R6 is initially configured as a RAID5 system, giving 5TB of storage, but users can change this to other RAID configurations [see picture].

RAID is a storage technology that allows a collection of hard disks to be aggregated, so they can function as a single so-called logical hard drive.

Users can specify how they wish their hard disks to function. For example, users can specify a RAID level that optimises the hard disks for performance at the expense of data redundancy: RAID 0. Users can also define a RAID level that optimises data redundancy at the expense of performance: RAID 10.

Review: Promise Technology Pegasus R6 Direct Attached Storage

Promise gives Mac users premier storage kit

Promise Technology's Pegasus R6 DAS system can be set up with RAID levels: RAID 0, 1E, 5, 6, 10 and 50, depending on the level of performance and data protection users want on their systems.

RAID 0 yields the highest performance as it splits data across all six disks (called striping). However, it does not store redundant data to be used in the event of a disk failure.

Normally, users would choose a RAID configuration like RAID 5, which gives good performance, but also offers some degree of protection against disk failure and consequent data loss.

Specifications

The Pegasus R6 DAS weighs about 9kg and is 25cm high, 20cm wide and 19cm long. Promise claims it has a maximum data transfer rate of 800MB/s, using the system configured as RAID 0, with a maximum power consumption of 78 watts and 55 watts in idle mode.

There are two Thunderbolt connections on the back of the Pegasus R6, allowing systems to be daisychained or connected to other Thunderbolt devices, such as Apple's Thunderbolt Display.

Performance figures

Transferring large data files from the onboard 256GB solid state device (SSD) on the MacBook Air to the Pegasus R6 DAS system gave a sequential read speed averaging just over 210MB/s.

To check performance of the Pegasus R6 system, we configured the system as RAID 0 to test full performance and as RAID 5 to check performance when the system also had some data redundancy.

We saw sequential read and write speeds averaging 650MB/s and 640MB/s for the Pegasus R6 system when configured as RAID 5. Converting this to Gbit/s would equate to 5.2Gbit/s, which is just over half of the Thunderbolt’s 10Gbit/s capacity.

With the system configured as RAID 0, we saw well over 700MB/s for both sequential reads and writes.

Such performance figures mean users will want to store large application datasets, such as CAD files or graphics/video files used in Adobe Photoshop or Premiere.

Conclusions

A good personal storage system for Apple Mac users whose systems have Thunderbolt connections.

We think that a gigabit Ethernet link would have given the system more appeal to small firms with older Mac hardware that may have wanted to attach it to their network.