H-P announced its FATA disk drives last year. The drives add a Fibre Channel (FC) interface to ATA drives and so provide, H-P claimed, the ability for an H-P array to house both online and nearline disks. The actual drives were developed with the help of Seagate and Hitachi GST.

EMC, IBM and HDS all offer arrays with mixed FC and SATA or ATA drives. HP is on its own with arrays offering FC and FATA drives. In fact, it's on its own with FATA drives. Throughout 2004 H-P developed its FATA offering and announced EVA arrays using the drives.

However the general H-P storage business fell behind its competitors and contributed to H-P bidding farewell to CEO Carly Fiorina earlier this year. At that point the H-P storage doldrums were revealed.

What does H-P actually think about FATA's future? Is it heading for the dumpster?

Daniel Martin, UK product marketing manager for H-P's StorageWorks, dismissed that idea convincingly. Are FATA drives an active part of H-P's EVA activities? "Yes, absolutely. FATA is very much a strategy of the EVA product line. One of the advantages of Fibre Channel connectivity to the drive is dual-porting. Another is mixing drives on a single shelf."

IBM, EMC and HDS offer arrays with mixed Fibre Channel and SATA drives. These are comparable to an H-P EVA array with mixed Fibre Channel and FATA drives. But there is a difference according to Martin: "Typically there is a separate SATA drive shelf with a Fibre Channel link to the shelf. H-P can mix Fibre Channel and FATA drives on the same shelf." So the space efficiency of H-P's mixed arrays is better potentially than those from EMC, HDS and IBM.

Does it worry Martin that H-P is on its own with FATA technology? "Is it a worry? Not for us, no. We see it as providing a customer solution. Otherwise they would have to buy a specific SATA shelf." That and the ability to dual-port the FATA drives - SATA drives can only be single-ported - means that: "We're selling a decent quantity of FATA drives."

Won't the other vendors' (commodity) SATA drives be cheaper than H-P's FATA drives? Martin said: "Potentially, yes. But then the customer would have to buy a specific shelf to house them."

Dual ports
SATA drives will get a dual channel capability when the revision 2 SATA specification is represented in drives. Martin reckons: "It's probably a year away." Giving drives dual-ported data paths provides greater reliability. It's common with Fibre Channel drives. IBM's xSeries Storage 250GB has dual ports already. A Broadcom BCM5771 enables SATA drives to be dual-ported. The Adaptec FS4500 Fibre SATA RAID box offers dual port access to each drive. These are in advance of the specification.

The SATA II dual port capability is active:passive whereas Fibre Channel drives generally have an active:active set up in which both controllers can talk to the drive at the same time. It's also important to note that SATA drive reliability is more to do with the drive mechanics than the presence or absence of dual ports.

It looks as if FATA drives do have a real future. However H-P will need to demonstrate significant financial savings to customers to convince them to buy an EVA mixed Fibre Channel/FATA array rather than a mixed Fibre Channel/SATA array from EMC, HDS or IBM.