Will 6Gb SAS kill Fibre Channel?

September 30, 2008 – 7:44 pm

Storage I/O trends

With the advent of 6Gb SAS (Serial Attached SCSI) which doubles the speed from earlier 3Gb along with other enhancements including longer cable distances up to 10m, does this mean that Fibre Channel will be threatened? Well, I’m sure some conspiracy theorist or iSCSI die hards might jump up and down and say yes, finally, even though some of the FCoE cheering section has already arranged a funeral or wake for FC even while Converged enhanced Ethernet based Fibre Channel over Ethernet (FCoE) and its complete ecosystem completely evolves.

Needless to say, SAS will be in your future, it may not be as a host server to storage system interconnect, however look for SAS high performance drives to appear sometime in the not so distant future. While over time, Fibre Channel based high performance disk drives can be expected to give way to SAS based disks, similar to how Parralel SCSI or even IBM SSA drives gave way to FC disks, SAS as a server to storage system interconnect will at leat for the forseeable future be more for smaller configurations, direct connect storage for blade centers, two server clusters, extremely cost sensitive environments that do not need or can afford a more expensive iSCSI, NAS let alone an FC or FCoE based solution.

So while larger storage systems over time can be expected to support high performance 3.5″ and 2.5″ SAS disks to replace FC disks, those systems will be accessed via FCoE, FC, iSCSI or NAS while mid-range and entry-level systems as they do today will see a mix of SAS, iSCSI, FC, NAS and in the future, some FCoE as well not to mention some InfiniBand based NAS or SRP for block access.

From an I/O virtualization (IOV) standpoint, keep an eye on whats taking place with the PCI SIG and Single Root IOV and multi-root IOV from a server I/O and I/O virtualization standpoint.

Ok, nuff said.

Cheers gs

Greg Schulz – Author Cloud and Virtual Data Storage Networking (CRC Press), The Green and Virtual Data Center (CRC Press) and Resilient Storage Networks (Elsevier)
twitter @storageio

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