Friday Jun 01, 2007
A new low. IBM has to do a huge amount of questionable math to try to make the POWER6 look good. You now have to go to IBM's website to see their press release, as it seems it
is very different than the one on launch date. http://www-03.ibm.com/press/us/en/pressrelease/21580.wss
But the bottom line is IBM uses totally bogus reasoning to try to make POWER6 look good in comparison to Sun. IBM says Sun has lower utilisation so you need to derate Sun systems by a bogus factor of THREE! Bull!
I've already posted last year http://blogs.sun.com/bmseer/entry/the_total_tyranny_of_low which stated "a significant number of Sun's large servers run at over 80% utilisation", and then also quoted
Computerworld which stated, "Dennis Callahan, CIO at The Guardian Life Insurance Company of America in New York, server utilization has shot up to nearly 50% in the past 18 months, with a goal in coming years of nearly 70%.
OK, on to the footnote with so much bull it stinks up the whole IBM press release. It really makes one understand that IBM really is on shaky ground with the POWER6, expensive, not that fast, and very slowly being released as we've covered in many posts since the IBM POWER6 launch. By the way I still have NOT seen system configuration, GHz, memory size and all details for the POWER6 "published wattage."
(3) This calculation is based on the trend toward consolidation of existing installed systems. Performance comparisons of the system were based on available benchmarks using the Java-based SPECjbb2005 benchmark (results as of 5/22/07: System p 570 (16-core, 8 chips, 2 chips per core, 4.7 GHz) SPECjbb2005 691,975 bops, 86497 bops/JVM; Sun Fire v890 (16-core, 8 chips, 2 chips per core) 1.5 GHz, SPECjbb2005 117,986 bops, 29,497 bops/JVM). A conservative 5 to 1 performance comparison was used. System utilization levels were derived from studies conducted by IBM of currently installed base of UNIX systems (available at www.ibm.com/servers/library/pdf/scorpion.pdf) and the recent trend on System p for utilizations levels well over 60% using advance virtualization technologies. 20% was used for the currently installed base of Sun Fire v890 systems and 60% for a virtualized System p 570. Higher utilization levels provide a 3 to 1 consolidation factor. Power consumption figures of 5600 W for the IBM System p 570 and 3200 W for the Sun Fire v890 were based on the maximum rates published by IBM and Sun Microsystems, respectively. Air conditioning power requirement estimated at 50% of system power requirement. Energy cost of $.092 per kWh is based on 2007 YTD US Average Retail price to commercial customers per US DOE at http://www.eia.doe.gov/cneaf/electricity/epm/table5_6_b.html as of 5/18/2007. For space calculations, two IBM System p 570 servers will fit in a single, standard rack. Assumed rates were 60% for IBM System p 570 and 20% for Sun Fire v890.
Thursday May 17, 2007
...sorry for the bad pun, but wattage is a huge concern at most datacenters.
- Vendors need to state watts/performance at full performance on benchmark
and not watts/performance at low utilisation. Datacenter managers
must plan and provision a datacenter knowing the peak watts.
There is no way they could count on poor (low) utilisation of servers
to keep their datacenters from frying.
- Need to use metrics of Watt/performance so it matches $/performance.
I've blogged about this before:
http://blogs.sun.com/bmseer/entry/power_performance_metrics
- Stop selling the advantage of brand new latest systems and
low utilisation. It matters not that there are lots of sloppy
low utilisation datacenters, because anyone buying new stuff if they
are not running at 50% or more are just wasteful and not worth
taking any advice from. I've blogged about this before:
http://blogs.sun.com/bmseer/entry/the_total_tyranny_of_low
These are some of thoughts after talking to a dozen customers this week.
Wednesday Nov 29, 2006
Don't be swayed too much by low-power saving technology hype. Don't look
at "wattage vs. utilisation", you really need to look at "perf/watt vs. utilisation". Perf/watt must be completely
constant over the utilisation curve if you think you can run a datacenter
at 15% utilisation and save money.
Check out my last posting and look at the last graph to understand the
issues.
Friday Nov 17, 2006
The Total Tyranny of low utilization datacenters
In this blog and other blogs I've commented on, Woodcrest supporters always
want to say their servers are better at low utilisation. This is
totally the wrong way to go! They first claim typical datacenters are
running at low utilisations, example: Xen claims typical datacenters are at 15%.
Horrible, HORRIBLE.
So why shouldn't use just add all kinds of techniques to power at lower
utilisations, clearly that is the best way to save money? Right? Wrong.
Lets take a simple example of a 400 watt server(@ 100%) that saves 20 watts for
each 10% reduction in utilisation. Will show this in a table below and
compare equivalent work done compared to 100% so you can see the hyperbolic nature of the curve. Of course I'm only looking at one server so there
is some discretisation but when you have a datacenter it will quickly
approach these numbers.
| %Utilisation |
100% |
90% |
80% |
70% |
60% |
50% |
40% |
30% |
20% |
10% |
0% |
| Watts-at-Util |
400 |
380 |
360 |
340 |
320 |
300 |
280 |
260 |
240 |
220 |
220 |
| watts/work |
400 |
422 |
450 |
486 |
533 |
600 |
700 |
867 |
1200 |
2200 |
inf. |
Now that I've got you shocked, let's look at a more typical example.
Lets compare 5 servers running at 10% utilisation (that is 220 watts
each or 1100 watts for the 5 of them). A single server running at
50% utilisation only uses 300 watts! The 10% case
almost require 3.7 times more power! OUCH!
Bottom line: It is far too easy to be fooled to think you are saving
money if power-saving features at low utilisation is your answer.
By the by, a significant number of Sun's large servers run at over
80% utilisation using Solaris, of course.
Here is an example from 2004 of someone on different products who likely understands this math.
As reported in
Computerworld:
"Dennis Callahan, CIO at The Guardian Life Insurance Company of America in New York, server utilization has shot up to nearly 50% in the past 18 months, with a goal in coming years of nearly 70%.
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