You have four basic ways to consolidate network-attached storage (NAS) data in your customers' environments.
1. NAS gateways
Gateways are good for organizations that want to consolidate their NAS data onto storage area network (SAN) storage. All of the major NAS vendors provide tools for data migration from their NAS storage to their gateway products. Although gateway performance and capacity is very good, it falls short compared to some of the available nontraditional alternatives -- giving you an opportunity to offer support. Gateways do provide more flexibility and scalability compared to integrated NAS boxes. For example, if you just want to upgrade back-end storage performance, you can do that separately from the NAS front end with NAS gateways.
2. Integrated NAS boxes
If SAN storage support isn't a requirement, you may want to use a NAS appliance with a NAS front-end and back-end storage integrated into one unit. It may be much easier to configure an integrated product than a gateway product because there are no SAN configuration issues.
3. Clustered and parallel file systems
Clustered file systems are good for companies with large computer clusters that need high-performance access to file system data. One key advantage of these products is that performance can be dialed up almost as high as you want by adding nodes to the cluster. However, these products may not be as useful for Windows users, as some have limited (or no) support for CIFS, but this is vendor-specific.
Clustered file systems operate across multiple nodes (generally more than eight) and use off-the-shelf hardware or standard operating system software. The nodes can be specialized, such as metadata nodes and storage nodes, or generic, supporting both metadata and storage services. A true clustered or parallel file system scales performance linearly as the number of nodes increases and provides access to the same data across all nodes.
Parallel file systems are similar to clustered file systems. They provide concurrent access to a single file across a number of nodes operating in parallel. This requires file data to be striped across multiple nodes, as well as special client software to process all file parts simultaneously. Companies with large computer clusters can take advantage of the massive performance scalability inherent in these products. It's important to check which operating systems a parallel file system supports, as there may be some limitations outside of Linux.
4. NAS aggregators
A new class of storage products provides an aggregated view of multiple, heterogeneous NAS boxes. These products provide a single GNS over all file systems for a set of NAS boxes. NAS aggregators, or network file managers, are great for companies consolidating NAS data from a number of different vendor NAS products or retaining multi-vendor NAS configurations. The primary advantage of these products is their support for a single namespace across all NAS boxes under their control. Their main disadvantage is that they add another box with additional overhead to the storage environment that needs to be installed, configured and maintained.
This article originally appeared in the December 2005 issue of "Storage" magazine.
About the author: Ray Lucchesi is president of Silverton Consulting.
