The deal is expected to be completed by the autumn, when StorageTek will be completely merged into Sun.
Claus Egge, IDC's programme director, European storage systems research, said, "StorageTek has a large installed base of users that will benefit in terms of service and support by having a big organisation like Sun on top of StorageTek itself.
"Sun customers will have a complete end-to-end portfolio of storage products."
He added that an IDC study of corporate storage systems buyers found that they preferred to buy storage from suppliers with a wide product portfolio, who could offer a one-stop shop and a single person to blame if things went wrong.
Sun's chairman and chief executive Scott McNealy, said, "This acquisition is part of an ongoing strategy to respond to customers seeking to rationalise their datacentre purchases to free up time and dollars to focus on compliance, architectural integration, security and, of course, the bottom line."