Re: [TUHS] Old mainframe I/O speed (was: core)

[Arthur Krewat <krewat@kilonet.net>]

On 6/24/2018 10:41 AM, Lawrence Stewart wrote:
> Glue or microcode NOPs or DRM licence unlock codes work, but they tend to damage your reputation.

I was called in at the last minute to help a consulting firm who was 
having a hard time convincing their customer that they knew what they 
were doing. They spec'd out a SunFire 4800 cluster back in the mid 
2000's that would run 10 or so medium-to-large OLTP and DW Oracle 
instances. I came across the notion of "Capacity On Demand" (COD) CPU 
licensing. You would buy a complete system, full of CPUS and memory, but 
only license a subset of the CPUs (and associated memory).

The customer thought "great!" we can save a few $'s and if we want, we 
can turn on the extra capacity when/if we need it.

After reading all the documentation, I was on a conference call with 
some Sun engineers, the sales rep, and my customer's team (including 
some of the consultants who were a little too "wet behind the ears".

I point-blank asked the engineers: "I see in the documentation that if 
you use COD, memory interleaving is turned off, which only makes sense. 
Since we're only licensing 3 of every 4 CPU, Doesn't that mean we're 
only going to get half if not one quarter of the platform's advertised 
memory bandwidth?" (Single vs. two-way vs. four-way interleaving. Odd 
number of CPUs, no interleaving). Reluctantly, one of the engineers 
agreed that was indeed the case. The other "engineers" had no freakin' 
clue, but muttered something about "we have to remember that for next 
time".

I roughly calculated the difference in my head and said: "For an extra 
2% of the entire project cost (IBM Shark, Oracle licenses and Sun 
hardware combined), we're going to hobble these systems that much?". 
After the consulting firm I was sub-contracting for balked on telling 
the customer about this extra cost, I mentioned this in the presentation 
for the customer's CIO. She perked up her ears and immediately said 
'We'll spend the extra for that much performance. What were you guys 
thinking?'" (referring to the original consulting firm's own "Sun 
expert" who I'd had a lot of arguments with, actually quit the day they 
signed the contract with Sun).

I wonder, to this day, how many Sun customers were sold this COD concept 
only to suffer through 1/2 or 1/4 the memory bandwidth. This was for the 
entire SunFire 3800/4800/4810/6800/E12K/E15K line.

I went on to support that system for 5 more years as the customer 
wouldn't let the consulting firm even THINK of letting me leave ;)

art k.