If this is a digital information age, then the job of watching where and how data is stored is a fundamental responsibility.

The protection and maintenance of enterprise data has increasingly come from external service providers, while dotting the landscape are web hosting, customer-facing file serving, and managed database and application offerings.

Increased emphasis on robust disaster recovery methods has also amplified interest in external file services, as many companies lack the internal capability to manage that much redundancy.

This high profile back-up task has reignited interest in dedicated file hosting services.

"There is a lot more business argument in favour of outsourcing the back-up data because you need it in a separate place, and organisations may or may not have suitably distributed data centres," said Graham Titterington, Ovum principal analyst.

Whether the bulk of corporate data is overseen by IT or service providers, Titterington estimates that enterprise storage requirements double every year, owing to greater focus on preserving data to meet regulatory requirements and an increase in email transmission.

"New technologies tend to be storage-hungry, using more video and audio," he said. This means that someone has to manage growth in disk space, and possibly disk management units and database structures.

Even some in the business of managed data aren't ready to say that outsourced data hosting and management is a universal need.

"I don't think it's as advanced as analysts and press comment may put it," explained Ian Massingham, director of hosting service delivery for Energis.

"But with an environment pressed to get more from IT spend, we are finding organisations are more open."

Where applications go, storage follows
That said, most storage hosting decisions beyond the back-up/disaster recovery model are not made because of the storage consideration alone.

Rather, the decision to host the business and technology operations which consume massive amounts of storage tend to be the guide.

"Eighty-odd per cent of our customers are running a database which drives something - an application, or a website," said Dominic Monkhouse, managing director of Rackspace Europe.

Companies looking to outsource can choose from a range of offerings, from simply handing over responsibility for an internal storage centre to contracting for shared or dedicated resources hosted and managed off-site.

While many firms employ some tactical outsourcing for specific purposes, such as hosting a website managed at an external location, "very few companies go the whole hog unless they are outsourcing their entire IT organisation", said Titterington.

Between are selective projects using co-location (physical hosting of customer-owned equipment which may or may not enjoy some service provider management), shared hosting (multiple clients using a single low-cost server but also lower performance and higher risk) and dedicated hosting, (where drives and servers are owned by the storage service provider but run for the sole benefit of a single client).

Shared responsibility models are common, where internal IT, via web or client/server-based management consoles, can still manage the files and the server as well as the on-site service provider.

While this can lower calls to the service bureau, the chain of command can get sticky if not clearly laid out.

"Sometimes customers will say 'we want to keep control of the OS', but you're not really helping yourself operationally," said Paul Rosher, head of infrastructure product management for BT, citing OS patching and maintenance as a significant crash-or-fly factor in the proper upkeep of storage servers.

Outsourcing options
Outsourcing can be an appealing choice at a juncture when a large component of enterprise storage is due for a rethink or overhaul, such as moving from direct attached server storage to a storage area network (San).

With iSCSI still something of a work-in-progress, Sans typically require the services of fibre channel experts, a skill not yet established in every organisation.

The case for some level of internal file hosting remains strong, both for control purposes and for speed.

Employees accustomed to Lan-speed performance in the tens or hundreds of megabits may balk at having that accessibility slashed dramatically if their day-to-day files are shifted to an external filestore accessed via VPN.

"We have seen a couple of RFPs requesting hosting of internal filestores, but not a lot," said Weynand Kuijpers, regional director northern Europe for hosting provider NTT/Verio.

With vendors such as Canon and Xerox introducing products that compete to keep those files internal, with elaborate document managing and imaging solutions, there are growing options to ease the pain of internal hosting.

A more popular use for hosted storage as a network hard disk is for companies that need to provide some level of managed storage to customers but lack a deep IT organisation.

Monkhouse says many of his customers use storage hosting in situations where they must, in turn, provide file-hosting capabilities to their customers, such as visual arts firms, ASPs, and systems integrators.