The worldwide external disk storage system market enjoyed its biggest growth in two years during Q2 2008 as EMC pulled away as the market’s top vendor, research from IDC has revealed.

The market as a whole was worth a global $5.1bn (£2.9bn), a rise of 16.7 per cent on the same period last year. Leading vendor EMC's quarterly revenue rose 19.7 per cent to $1.1bn as its market share leapt more than half a point to 21.7 per cent. IBM overtook HP to move into second spot, as Big Blue saw revenue rise 14.3 per cent to $667m, giving it a market share of 13.1 per cent.

HP's market share dropped a point to 12.9 per cent as revenue rose 8.2 per cent $655m. Dell, which has included revenues from acquisition EqualLogic since Q1 2008, hung on to fourth spot as revenues grew 15.7 per cent and market share stood at 9.2 per cent.

NetApp and Hitachi swapped places in fifth and sixth. The former moved up a place on the back of a 17.2 per cent spike in revenue, which stood at $404m, giving it an eight per cent market share. Hitachi's revenue grew 9.8 per cent to $384m, leaving it outside the top five with a market share of 7.6 per cent. All other vendors accounted for 27.5 per cent of the market as their revenue grew 22.7 per cent to $1.4bn.

Natalya Yezhkova, IDC's research manager for storage systems, said: "Despite concerns about a 2008 slowdown in IT spending, external disk storage systems spending experienced strong growth in the first half of 2008. The second quarter of the year was remarkable, not only because it is the highest growth in two years, but also because of the distribution of this growth across different market segments.

"The ability of vendors to meet a variety of needs among customers with a diversity of storage products and initiatives led to solid growth across all installation environments, even in those that declined over the past several quarters."

The open SAN market grew 15.5 per cent in Q2 2007 and was led by EMC with a 23.9 per cent market share, followed by HP with 16.7 per cent. The iSCSI SAN market enjoyed 93.9 per cent revenue growth with Dell leading the way with 32.8 per cent market share. The NAS market grew by 23.5 per cent and EMC again led the way, holding almost two fifths of the market. NetApp took second spot with a 28.5 per cent market share.

The total network disk storage market grew by 22 per cent on last year and was worth more than $3.8bn. EMC dominated the market and held a 26.4 per cent market share. This was more than double its nearest rival HP, which took a 12.9 per cent slice of the market.

The total worldwide disk storage systems market grew by 10.9 per cent and was worth almost $7bn. HP led the way with an 18.1 per cent market share, despite revenues declining 1.2 per cent to $1.25bn. IBM clung on to second as its revenue rose 2.6 per cent to $1.23bn, giving it a market share of 17.7 per cent.

EMC made ground in third, as revenue increased 19.7 per cent to $1.1bn, giving it a 15.9 per cent market share. Dell, in fourth spot, also performed solidly, with revenue rising 14.2 per cent to $694m giving the vendor a market share of 10 per cent.

Completing the top five, Sun Microsystems enjoyed a strong quarter with revenue rising 29.2 per cent to $494m and market share up a point to 7.1 per cent. All other vendors saw revenue rise 15.2 per cent to $2.15bn, giving them a market share of 31.1 per cent.