Solaris SCSI Target

My colleagues across the aisle (and some across the ocean) released COMSTAR today. COMSTAR allows OpenSolaris to be a SCSI target.

Why is this interesting? Traditionally companies buy a dedicated RAID controller to store their data - something like this or this.  RAID controllers usually have special ASICS to compute the redundant data. The hardware boards are specially designed.  Their software is usually closed source, so it's impossible for end users to modify. The development environment varies a lot, sometimes it's a home grown operating system that's difficult to use, sometimes it's bought from different embedded OS vendors, but hard to modify.  Because the market for RAID controllers is relatively small and fragmented, the high fixed  R&D costs are not spread over much volume.

Enter COMSTAR. COMSTAR is the last link in being able to create a SCSI storage array using Solaris (actually you could do it before with iSCSI, but COMSTAR is flexible enough to support any transport).  With Solaris, you can do RAID in software doing ZFS.  CPU cycles are increasing due to multicore technology, especially relative to the speed of disks, so it's realistic to do RAID calculations in software, instead of costly dedicated ASICs.  You can attach nearly any kind of disk you want. You have a stable development environment. You can use commodity PC hardware.  You want to export some disks as NFS or CIFS, you can do that too.  And the code is free, along with a pretty good development environment.

Will we cause traditional RAID vendors to lose sales this week?  Probably not, because there are lots of things that dedicated RAID controllers can do that we still can not do. Today, there's no management story - you're left using Solaris system administration skills. The system level redundancy that high end RAID systems provide isn't there.

But for many people, COMSTAR and Solaris will provide a viable solution.  I see it as disruptive technology. Today, it fits the needs low end users. These users are comfortable administering Solaris, and assembling hardware. They understand and accept the limitations of the solutions.   But, with time, the additional requirements that higher end users require will slowly be filled by developers.