The boost in storage has come along with investments in cloud computing and data-center virtualization, IDC analyst Liz Conner said. Companies are updating their storage systems for the era of "big data," to deal with huge and growing volumes of information, she said.

The total market for disk storage systems grew just over 10 percent from last year's second quarter to reach almost US$7.5 billion in revenue, IDC said in its Worldwide Quarterly Disk Storage Systems Tracker. IDC defines disk storage systems as collections of three or more drives, either in or outside servers.

External disk storage grew 12.2 percent year over year to slightly more than $5.6 billion in factory revenue, IDC said.

The revenue gains came on top of strong results from last year's second quarter, when the industry was recovering from the recession of 2008-2009, Conner said. The total amount of capacity delivered also continued to rise, with total disk storage systems shipped in the quarter representing 5,353 petabytes of capacity, up 46.7 percent from a year earlier. In the second quarter of 2010, there were 3,645 petabytes sold, a 54.6 percent increase.

Sales increased across all major product categories, including NAS (network-attached storage) and all types of SANs (storage-area networks). The total market for non-mainframe networked storage systems, including NAS and iSCSI (Internet SCSI) SANs, grew 15.0 percent from a year earlier to $4.8 billion in revenue, IDC reported. EMC led that market with 31.9 percent of total revenue, followed by NetApp with a 15.0 percent share.