NAS Basics
You can never be too rich, too thin or have enough storage. And buyers are increasingly reaching for network attached storage (NAS) products when their digital media collections outgrow PC-bound hard drives. Fortunately, there are many options available, with more hitting store shelves all the time.
NAS devices generally fall into four categories:
- Single drive diskful
These come with drives installed (usually not replaceable or upgradable) and usually have USB 2.0 ports to support expansion via external USB drives. There are many feature variations including built-in FTP and HTTP servers, BitTorrent clients, USB print servers, streaming media servers and backup utilities. Older models have ATA/IDE drives, while newer products use faster SATA drives. - Single drive diskless (BYOD)
These Bring Your Own Drive products accept 3.5″ IDE or SATA drives and are a good way to save money by reusing a drive left over from upgrading a PC’s internal storage. There are also models that accept external USB drives. Features are similar to those in diskful products. - Multi drive diskful
The two advantages of multi-drive NASes are more storage space and RAID – a technology that can provide protection from inevitable disk failure. The key disadvantage is cost, which can be managed by purchasing BYOD products and models supporting fewer drives. You’ll find the same feature sets as in single-drive products (with the exception of RAID). - Multi drive diskless (BYOD)
These products combine the potential cost-savings of BYOD with the feature and functional advantages of multiple drives.
The Charts
The key performance criteria for NASes are read and write throughput. Other specifications that you might focus on for selecting a naked hard drive such as access time, seek time, etc. are generally masked by the overhead of moving data across a network. Factors that do affect throughput include network connection speed, file size and file record size.
We use iozone as our performance test tool, with the procedure described here. You’ll find charts for read and write Performance using 100 Mbps and 1 Gbps LAN connections and file sizes of 64 MB, 256 MB and 1 GB. Of course, the speed and operating system of the computer doing the reading and writing has a direct effect on performance, so we try to minimize that effect by using as few test systems as possible. The use of different test systems is indicated in the charts by different colored bars.
You’ll also find Product Feature Tables that summarize key product specs. Related reviews are easy to get to since they’re available via links in the Product Feature Tables or just clicking on a product’s bar in the Performance charts.
Unless otherwise noted, all products have the following features:
- Web-based admin interfaces
- Auto MDI/X 10/100 Ethernet port
- SMB/CIFS network file system support (works with most OSes, but not the most efficient network file system out there)
We’ll be adding products to the charts on an ongoing basis and hope you’ll find them useful. We’d also like to enhance the charts to better serve your needs, so be sure to use the discussion link below to give us feedback.