[ryao]

> There was nothing that specific about Solaris that made sense for ZFS, and even less of a connection to the SPARC architecture.

Although it does not change the answer to the original question, I have long been under the impression that part of the design of ZFS had been influenced by the Niagara processor. The heavily threaded ZIO pipeline had been so forward thinking that it is difficult to imagine anyone devising it unless they were thinking of the future that the Niagara processor represented.

Am I correct to think that or did knowledge of the upcoming Niagara processor not shape design decisions at all?

By the way, why did Thumper use an AMD Opteron over the UltraSPARC T1 (Niagara)? That decision seems contrary to idea of putting all of the wood behind one arrow.

[bcantrill]

Niagara did not shape design decisions at all -- remember that Niagara was really only doing on a single socket what we had already done on large SMP machines (e.g., Starfire/Starcat). What did shape design decisions -- or at least informed thinking -- was a belief that all main memory would be non-volatile within the lifespan of ZFS. (Still possible, of course!) I don't know that there are any true artifacts of that within ZFS, but I would say that it affected thinking much more than Niagara.

As for Thumper using Opteron over Niagara: that was due to many reasons, both technological (Niagara was interesting but not world-beating) and organizational (Thumper was a result of the acquisition of Kealia, which was independently developing on AMD).

[ryao]

Thanks. I had been unaware of the Starfire/Starcat machines.

[ahl]

I don’t recall that being the case. Bonwick had been thinking about ZFS for at least a couple of years. Matt Ahrens joined Sun (with me) in 2001. The Afara acquisition didn’t close until 2002. Niagara certainly was tantalizing but it wasn’t a primary design consideration. As I recall, AMD was head and shoulders above everything else in terms of IO capacity. Sun was never very good (during my tenure there) at coordination or holistic strategy.