Nexsan’s introduction of 3 TB SATA hard disk drives (HDDs) into its E-Series™ storage systems made it the first enterprise storage vendor to offer storage arrays with these size HDDs in them. But the stories behind the headline are the QUALITY of HDDs that Nexsan uses in its storage array and the enhancements that Nexsan made to its storage controllers to support them. These underlying features should instead contribute to users having the same or even higher uptime and performance expectations than they had in the past when using Nexsan storage systems.
The announcement that Nexsan E-Series storage systems support 3 TB SATA HDDs is certainly a welcome relief to those organizations looking to more efficiently store data on the same size or smaller data center footprints. But larger SATA HDDs are being greeted with apprehension by some as concerns about RAID rebuild times mount.
This is of specific concern among managed service providers (MSPs) that may manage hundreds or even thousands of HDDs. Just recently I spoke to an MSP in Florida that needed to alter how it was buying storage arrays because of SATA rebuild times.
It was finding that as much as 10% of its storage system’s processor was being consumed by doing rebuilds of failed 1 and 2 SATA HDDs in its RAID sets. To compensate for that loss of productivity it was buying storage arrays with extra processing power and storage capacity. However this change could in effect negate some of the benefits that 3 TB SATA HDDs potentially offer.
In discussing this MSP’s concern with Nexsan’s CTO, Gary Watson, he cautioned that some organizations have a tendency to buy commodity storage arrays. Then they attempt to make it up for it with features like RAID and redundancy. He says, “That’s a losing proposition. Components internal to these storage arrays are apt to fail more quickly so a lot of data center bandwidth is spent on managing and moving data around.“
To avoid that scenario, Nexsan first qualifies the 3 TB SATA HDDs that are deployed into its systems (E-Series and others) to mitigate the possibility of downtime. In this way, if it detects that HDDs from a specific vendor or of a specific model are not meeting its reliability or performance standards, it does not use that drive.
This qualification process has helped Nexsan to drive failure rates on its storage arrays to well below a half percent per year. Watson adds, “At .5 % data centers are not going to see any appreciable impact on their data center performance when rebuilds occur, if they see anything at all.“
A second step that Nexsan took even before it introduced the 3 TB SATA HDDs was an upgrade in the architecture of the controllers used in the E-Series. Prior generations of HDDs also benefit from these upgrades. However these upgrades were specifically done in anticipation of the higher capacity and higher performing HDDs that Nexsan knew were coming down the pike.
These enhancements include:
- A transition in the controller from an internal 64-bit PCI-X architecture to PCI Express (PCIe) GEN 2. This provides each device with its own bandwidth limit and eliminates the sharing of bandwidth between devices. The net result is better access and throughput to E-Series HDDs by applications.
- Replacing DDR SDRAM with DDR3 SDRAM. This increases its memory bandwidth by about 2.5x which should result in overall application performance gains.
- Re-engineering its ASIC used for RAID 5 and RAID 6 to improve RAID performance and rebuild times
It is this combination of E-Series new controller features, Nexsan’s history of only using qualified enterprise drives and its inherent Active Drawer and Vibration Control technologies that should alleviate any user concerns they may have about deploying these new 3 TB drives in Nexsan E-Series. This combination of features should instead free them to capitalize on the higher density and improved performance that the E-Series storage arrays can deliver so they confidently use them in support of a widening range of applications.