Toshiba today rolled out the first product to come from the hard drive business it acquired from Fujitsu last year: a 600 GB 2.5-inch SAS hard disk drive. Last week, Seagate launched a 600 GB 2.5-inch drive of its own, a 10,000 RPM offering with the option of Fibre Channel or SAS drive interfaces.
At 600 GB capacity, small form factor (2.5-inch) SAS moves into closer competition with Fibre Channel disk drives in the external storage market. Analysts say the transition to small form factor SAS is largely complete in internal storage, but the conversion of external storage from FC to SAS disks has been a long process.
It was only about 18 months ago, pointed out IDC analyst John Rydning, that the SAS-2 spec was ratified, boosting SAS throughput speeds to 6 Gbps (Fibre Channel is now at 8 Gbps). That fairly recent spec also supported cable lengths between drives of up to 10 meters, more suitable for external disk arrays than the previous limit of six meters.
Meanwhile, until these announcements from Seagate and Toshiba, aerial density on SAS drives, particularly in small form factors, also lagged behind the FC gear the enterprise is accustomed to, Rydning said. “These announcements bring 2.5-inch capacity parity with 3.5-inch Fibre Channel drives that are still primarily used [in external storage systems], creating a migration path for external storage players [to small form factor SAS drives],” he said.
This is a transition Rydning said he expects to continue over the next three years, provided external storage products using small form factor SAS drives work as expected out of the gate. Even then, however, the transition will also depend on the comfort level for storage pros charged with managing systems day to day. “People have built up a knowledge base and comfort level with Fibre Channel — there’s hesitancy to make sure SAS is as robust,” Rydning said.