Data protection company Iron Mountain is buying LiveVault, a provider of online server backup and recovery services.

The companies know each other well. Iron Mountain has been an investor in LiveVault since 2000 and already owns nearly 14 percent of the company. Iron Mountain will pay about US$42 million for the rest of it.

The companies have also partnered for the past five years, with Iron Mountain serving as LiveVault's largest sales channel.

LiveVault offers disk-based backup and recovery for small and midsize companies as well as for remote offices of larger companies. The company claims to have more than 2,000 corporate customers.

The buyout complements Iron Mountain's acquisition last year of Connected, a provider of PC backup and recovery offerings.