GridStore NASg: First Look

GridStore NASg: Network Attached Storage Nodes

By Logan G. Harbaugh, SSG-NOW Validation Engineer



Typically network attached storage (NAS) consists a group of drives in a large enclosure, and expanding that system involves another drive-filled enclosure connected to the first.

GridStore uses an entirely different model – a number of low-cost small boxes, based on the Intel Atom 330 processor, each containing 1GB RAM and a single hard drive, set up in a many-to-many grid, with unlimited storage and client nodes.

SSG-NOW tested the final beta (1.0.13) version of GridStore NASg with pre-production hardware, and the system worked well enough to validate the GridStore’s basic concept. With excellent scalability and low-power, low-noise nodes, the GridStore system shows a lot of potential.

GridStore supplied eight nodes, all based on the Intel Atom D510 1.6GHz processor and running Windows 7 embedded. The grid was also tested with several additional nodes, both server and client systems running Windows Vista Business Edition, Windows 7 Ultimate and Windows Server 2003. In each case, the GridStore software installed smoothly and the systems were simple to discover and add to the grid. The nodes are very quiet, and draw very little power, especially when the grid is not being accessed.

GridStore uses specialized software drivers to allow both client and storage nodes to connect to the grid. This software worked smoothly and didn’t cause any problems during testing. Management is done through a Microsoft Management Console (MMC) plug-in.

The GridStore installer software installs GridStore on the first node, and can install the software to other available Windows systems if administrator access is provided.

Once the software is installed on all nodes, each node can be designated a client, a server or both. Servers provide storage, clients can access the GridStore volume – each node can do one or both.

Management features were much better realized than with the previous early beta we tested. Volumes can be modified, nodes can be added or subtracted and the GridStore volume is automatically resized. Nodes can also be switched from client to server and back. security settings and access control are not yet available.

Once the software is installed on all nodes, each node can be designated a client, a server or both. Servers provide storage, clients can access the GridStore volume – each node can do one or both.

Volume size is now accurately reported, but some features such as security settings and access control are not yet available security settings and access control are not yet available.

Storage Nodes	NASg Desktop Storage Node	NASg 1U Rackmount Network Storage Node
OS	Windows 7 embedded	Windows 7 embedded
CPU	Intel Atom D510	Intel Atom D510
RAM	1 GB RAM	1 GB RAM
Network Interface	1 x GbitE NIC	1 x GbitE NIC
Hard Drives	1 x 1 TB SATA II HDD (300 Gbit/s)	2 x 1 TB SATA II HDD (300 Gbit/s)
	Price $400	Price $480

Multiple volumes can now be created, and each can be tuned for more storage or more redundancy by increasing or decreasing the number of redundant nodes in the grid. Much like RAID 6, multiple parity nodes can be created, ensuring that even if multiple nodes fail simultaneously, the overall volume is still accessible.

Testing of the system focused on scalability, which was excellent. Given the moderate increases in load on the systems with additional clients, it seems likely that a grid of 20 storage nodes and 100 or more client nodes would be feasible with good performance.

Since the system is still in beta and drivers have not been optimized, testing with IOMeter or other such tools was not attempted. A grid with four storage nodes was created, and six client nodes were set up. Large folders (8.73GB in size) were copied from the clients to the grid volume, and then the folders were copied back to the clients, and throughput was monitored as copies were started to and from each client. As each additional client copy started, throughput on copies that had already started did not drop, indicating that storage nodes were able to sustain as much throughput as the Windows clients were able to support. During copies, CPU utilization averaged 39.7% on clients and 4% per copy started on storage nodes, whether copying from the GridStore volume to client nodes or from client nodes to the GridStore volume.

Number of nodes copying file from GridStore volume (f:\) to local client disk:	Average load on each of four server nodes
1 client node	8.0%
2 client nodes	12.1%
3 client nodes	17.3%
4 client nodes	22.2%
5 client nodes	27.1%
6 client nodes	32.0%

Average copy speed was 8.8MB/sec. on all four clients, regardless of how many were in process, regardless of OS version or CPU. Downloads took 28 minutes each for all six client nodes, indicating that throughputs were constant at about 8.8 MB/sec. regardless of the number of downloads in progress, which should mean that effective bandwidth was limited by the clients rather than the server nodes. When the process was repeated in the other direction, load results were nearly identical, though throughput was slightly less, at 8.1 MB/sec. and 32 minutes.

SSG-NOW Assessment

While the software we tested was not the release candidate, the potential is obvious. Rather than buying a large, expensive NAS system or SAN, small and mid-size businesses can purchase inexpensive nodes as needed, adding additional nodes to an existing grid. At $400-480 per node, the cost per terabyte is low, and functionality should be ideal for file sharing and other applications that would normally make use of network attached storage. GridStore’s NASg is also very scalable – a configuration of twenty storage nodes would yield a 40TB array, but with very low noise and power consumption.