Most storage solutions are optimized for fast access and frequent updates, a formula that fits the requirements of transactional applications to a tee but isn't necessarily well suited to archiving files that - whether by law, or policy, or practice - either must not or will not be changed.

As a sweeping simplification, this "fixed content" - such as legal documents, financial data cutoff, engineering diagrams, medical images, audio files, and video files - are ready for archiving the instant they're created. Using a tiered storage approach to managing them makes little sense. Moreover, these files typically produce large archives that must be maintained for a long time, which makes the conventional approach to data protection, namely tape backup, difficult and expensive to implement.

As a result, storage vendors have begun supporting fixed-content archiving with specialized lines of products, separate from their transactional offerings, and have put a great deal of emphasis on reliability and simplified administration in these products.

Sun's StorageTek 5800, a.k.a. Honeycomb, addresses fixed-content archiving needs with a resilient, cell-based solution that can scale from 8 to 16 nodes per cell (a half rack), or up to 32 nodes in a single rack, and can be expanded further by adding more cells.

Sun has taken a different approach to companion software than vendors such as EMC, Hitachi, and HP, which have married their fixed-content archiving solutions to compliance applications. (Like Honeycomb, the HP solution is based on cells; I reviewed the debut version, which focused on e-mail archiving, in early 2006. Since then, HP has rounded out the application offerings.) Sun has not wedded Honeycomb to any specific application, leaving that task to partners and customers. The upside of Honeycomb's openness is that the possibilities are endless. In fact, Honeycomb's powerful, built-in administrative software is complemented by an SDK that allows Java or C developers to define their own metadata schemas consistent with the specifics of their application. Recently Sun made the Honeycomb software publicly available at OpenSolaris.org, as StorageTek 5800 Open Edition, under the BSD license. A software emulator of the ST5800 to run applications built using the SDK is also available for download.

Inside the Honeycomb

For logistical reasons, I conducted my evaluation of the ST5800 at one of Sun's labs in the US. My test unit was a fully populated, 16-node cell connected to three client machines running Sun Solaris, Red Hat Enterprise Linux, and Windows Server 2003.

Each Honeycomb node is essentially a server running Solaris 10 and the ST5800 application software. Each server mounts four 500GB SATA drives and connects via redundant links to two GbE switches. The redundant switches are integral components of the cell and, of course, provide protection against a failure of either one.

Of the 16 nodes, one is the elective master and coordinates the activities of the other nodes, but the system has a mechanism to quickly and automatically replace a failed master with another node, which is just one example of the reliability features built into the ST5800 (more on this later).