Five years ago, few companies would have seen email as a mission-critical business tool. Most now do.

As Mr George Symons, chief technology officer of storage software company Legato, says: "Email is the only application where the chief executive will call you at 2 a.m. if it's down."

And it is not that Mr Symons's boss is especially prone to disturbing his team's sleep. A separate survey, carried out by rival software firm Veritas, found that three in four IT managers feared for their jobs in the event of a serious email crash. Despite this, Veritas's chief information officer, Mr Greg Valdez, said as many as 56 per cent of companies do not even include email data in their regular back-up routines.

While the accounts package or the customer relationship management (CRM) application is backed up daily, most companies risk losing the vast amount of valuable information locked away in staff mailboxes. Should a disaster strike, losing this information could make it far harder for businesses to return to normal.

The problem is aggravated because email systems are often developed in a piecemeal manner, installing servers running Microsoft Exchange or Lotus Notes on a departmental basis. Between them, Notes and Exchange account for 80 per cent of all business email applications. In most cases, these systems have not been designed to handle large numbers of users or mission-critical data.

Mr Anders Lofgren of Forrester Research notes that the problem is made worse where companies have separate IT administration for email and storage. Email technicians might not have the skills to build a truly robust system.

As a result, an "ecosystem" of independent software companies has developed around Exchange, and, to an extent, Notes. These companies claim to add the resilience of high-end systems to email server programs, even when they run on relatively low-end Windows servers.

These products are gaining ground because they work with, rather than in the place of, existing email systems, and protect companies' software investments. There are choices: Oracle offers its own email database, which the company claims is more robust than Exchange, yet still works with Outlook. Other companies, such as Mirapoint, provide dedicated hardware platforms for running email.

Even when these alternatives work with Outlook or Notes, however, they still need to be supported by strong back-up for business continuity.

Forrester lists Veritas, IBM's Tivoli division, Computer Associates, Legato and CommVault as software companies with an email offering; among hardware vendors Mr Lofgren also points to HP and EMC.

In companies that depend more heavily still on email, such as e-commerce operations, IT departments are moving email over to storage area networks.

This enables faster data replication and takes up less storage space. A storage area network can also be designed to give an email server dual paths to its storage, further cutting the risk of downtime.

This can be necessary because staff's view of email has changed. Environments such as Microsoft Exchange and Outlook are no longer simply for messaging. As Microsoft has added functions such as calendars, shared address books and task management tools to Outlook, the program has become deeply embedded in the workflows of many thousands of businesses.

"Individuals use email as their filing system and database," says Ms Dana Gardner, an analyst at Yankee Group. "In a large company you are dealing with a highly scaled exchange environment and a large amount of data."

Mr Dan Sarta of consultants AT Kearney said companies appear more interested in cutting down on spam or in securing confidential information than in the resilience of email systems themselves. If that is the case, IT managers had better hope they are not sleeping too soundly when the chief executive calls.  - (Financial Times Service)