Even as the worldwide external disk storage market remains in decline, certain categories continue to show double-digit growth – categories likely to be sold by solution providers.

iSCSI SAN (storage area networks) grew by 57.2 percent year over year in Q2 and fiber channel SAN grew by 66.8 percent for the same period, both in price bands of less than $15,000 – a trend driven by customers demanding enterprise level network storage at a friendlier price point, according to a new report from market research firm IDC.

Midrange NAS (network attached storage) in the price band between $15,000 and $50,000 also saw year-over-year growth of 20.7 percent.

But overall, worldwide external disk storage systems factor revenues saw a decline of 18.8 percent year-over-year for Q2, totaling $4.1 billion. Total disk storage systems factory revenues fell to $5.7 billion, an 18.7 percent decline in Q2 year-over-year. IDC says the weakness was driven by a tough sales environment for server systems sales.

In terms of market share, EMC maintained its lead in the external disk storage systems market with 21.5 percent revenue share in Q2 followed by IBM with 14.9 percent share, and HP in third place with 11.4 percent share. Dell had 9.8 percent share and NetApp had 8.9 percent share.

"While all vendors are down year-over-year, we are beginning to see several storage vendors whose external disk storage revenues are showing sequential quarter-over-quarter growth, indicating some stability beginning to take shape in the market," says Steve Scully, research manager, for Enterprise Storage at IDC, in a prepared statement.

The total network disk storage market, which IDC defines as NAS Combined with Open iSCSI SAN, declined 15.3 percent year-over-year to more than $3.2 billion in revenues, according to IDC. EMC maintains the market lead with 26 percent revenue share followed by IBM with 13.8 percent revenue share.

More specifically, in the open SAN market, which declined 23.8 percent year-over-year, EMC led with 23.1 percent revenue share.

The NAS market declined by 6.8 percent year-over-year, and was led by EMC with a 38.7 revenue share followed by NetApp with 26.1 percent share.

The iSCSI SAN market grew by 27.2 percent in revenue, with Dell leading in market share with 35.3 percent followed by EMC with 15.7 percent.