GlassHouse will manage infrastructure, automate manual processes, streamline IT operations, and potentially reduce costs.
The team will lead an infrastructure upgrade at the firm, initially focusing on workspace management, exchange migrations and archiving.
"The GlassHouse team is located on-site in our London office," said Clive Knott, IT director at Olswang.
"They broadly work for me, though the relationship with GlassHouse means that GlassHouse is responsible for backup and managing the service."
The IT division is made up of the service desk, the technical team, the development team and communication executives.
Knott says the fact that the GlassHouse team is on-site reinforces the law firm's data compliance, because the outsourced staff is essentially under his control and a part of the Olswang team, though they have signed confidentiality statements.
Olswang had previously outsourced the IT division to Ultima Business Solutions, but opted to select GlassHouse to manage the service for the next three years after a review.
"Our rapid growth and drive to expand globally necessitated a more strategic approach to better manage our existing and newly acquired operations," said Knott.
"With GlassHouse's expert team, we are outsourcing our IT operations to a knowledgeable third party to automate processes, reduce costs, and improve efficiency across our organisation."
Olswang also plans to install a new storage area network as part of the infrastructure upgrade, and Knott has gone out to tender with NetApp, EMC and Dell.