The NST Series Unified Storage System platform is designed to move network-attached storage (NAS) and iSCSI traffic through a single controller. The unified storage architecture is an extension of the Nexsan E5000 NAS system launched in August 2011.
The NST’s three models -- the 5100, 5300 and 5500 -- can run iSCSI and NAS together, or either of the protocols alone. A customer can start out with iSCSI or NAS and upgrade to unified storage. The systems don't support Fibre Channel (FC) networking.
Nexsan executives maintain that the system is truly multiprotocol because it supports block and file storage through one controller instead of through separate controllers.
“Lots of people use the term ‘unified,’” said Mark Peters, senior analyst at Enterprise Strategy Group (ESG) in Milford, Mass. “But behind the scenes, they're not. They've taken two existing systems and written software that stitches the two systems together. Nexsan is doing a genuine unified system.”
Don Chouinard, Nexsan’s director of product marketing, said that of the NST’s main competitors -- the Dell Compellent zNAS and Dell EqualLogic FS7500 NAS, EMC VNX5500 and NetApp FAS3200 -- only NetApp is a true unified system. Both of Dell’s systems require separate physical devices for NAS and storage-area network (SAN), and the VNX uses an X-blade in its chassis for file access. However, all of them let customers manage block and file storage through one interface.
The NST devices use Nexsan’s SSD FASTier cache introduced with the E5000 NAS array in August. FASTier holds DRAM, as well as 100 GB or 200 GB of SSD to accelerate performance for applications with random I/O. A 16-bay SAS bus interface sits in front of the NST’s dual, active-active controllers. One bay is reserved to contain DRAM, while the rest of the bays contain the SSDs.
Chouinard said the write journal is mirrored to the DRAM, so a redundant controller can access the write journal from the DRAM if the other controller dies.
“It’s another level of data protection and it’s particularly important for random I/O applications,” said Christine Taylor, an analyst at Taneja Group in Hopkinton, Mass. “It holds a record of the write journal in the controller and DRAM, and it’s enormously fast.”
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The NST platform supports between four to 24 Xeon CPU cores; 12 GB to 192 GB of DDR3 DRAM; up to 12 dedicated RAID engines; and up to 360 15,000 rpm SAS, 7,200 rpm SATA or SSD drives. The FASTier Cache can hold up to 16 SSDs, or up to 3 TB (with expansion shelves) that's accessible by both controllers. The systems’ front end has up to 12 Gigabit Ethernet (GbE) ports or up to four 10 GbE ports, while the back end can hold up to 12 8 Gbps Fibre Channel ports.
The entry-level NST5100 has a single four-core Intel Xeon processor with 12 GB of memory per controller and a maximum of 93 TB of capacity. The NST5300 is available with one or two four-core Xeon processors, 24 GB or 48 GB of memory per controller, and up to 720 TB of storage. The NST5500 includes two six-core Xeon processors, 48 GB or 96 GB of memory per controller, and up to 1 PB of storage. The FASTier Cache for all models includes 8 GB of RAM. The 5100 has 100 GB of SSD, the 5300 has 200 GB of SSD and the 5500 has 400 GB of SSD built in. FASTier Cache Expansion shelves are available for the two higher models.
“We can give you high performance with the SATA and FASTier, or we can offer screaming performance with SAS and FASTier,” Nexsan’s Chouinard said.
All three models offer up to 64 TB logical unit numbers (LUNs) on the iSCSI SAN for thin provisioning. The systems also have asynchronous and synchronous replication, application-consistent snapshots via the Microsoft Volume Shadow Copy Service (VSS) infrastructure, or manual snapshots for Linux and Unix servers.
Pricing starts at $16,000 for the 5100, $87,000 for the 5300 and $111,000 for the 5500.