Hi,

A client of mine is inthe process of upgrading from AS 32-bit to
64-bit.

We've done some initial testing of cube builds, with 3 dimensions and
2 measures. And have noticed that on the new dual processor Itanium2
servers the processors are being hammered. At times spending up to 5
minutes maxed our on 100% usage.

Has anyone else had any experience with 64-bit Analysis Services on
Itanium2 servers? And have seen this behaviour before?

It could be that the old servers had bottlenecks at the IO disk level,
which meant the processors weren't being hammered. And now the servers
are running on an IBM SAN, so the bottleneck has now shifted to the
processors.

But if anyone has any thoughts on this, then they would be much
appreciated.

Cheers,
Reece.

It is not uncommon at all to see CPUs go to 100% during processing on good
quality server hardware (32-bit or 64-bit). There are two resources you
should spend some time with. First is the Analysis Services Performance
Guide
(http://www.microsoft.com/technet/pro...n/ansvcspg.msp
x), which has a *large* and detailed section on improving Processing
performance. Second, you should look at the "Getting Started with Analysis
Services 64-bit" white paper at:
http://www.microsoft.com/technet/pro.../ansvcs64.mspx

The second white paper is important because with Analysis Services, the
expanded capacity of a 64-bit system is almost totally around greatly
expanded *capabilities* and not around pure performance. You will find that
(with one exception) performance is just about equal between a 64-bit system
and a 32-bit system (given equivalent clock speeds, I/O subsystem, etc.).
The one exception in performance is that on 64-bit system you can have a
HUGE process buffer size. So if you have a lot of aggregates that need to be
calculated in Processing; or if the aggregates are big -- and you are
finding that you are having to go to temp files during processing even if
you've enabled /3GB on 32-bit and increased the process buffer size to the
maximum, or if you are doing Processing in parallel and you have a lot of
requests going at the same time (which will also force temp files) -- then
with a 64-bit system you can eliminate all of the overhead of using temp
files (which is almost 10X slower in Processing if you end up going to temp
files) by setting a huge process buffer size. On a 32-bit system you are
limited to about a 2GB max process buffer size -- with a 64-bit system you
can go as high as you have physical memory (I've ran on a system with a 20GB
process buffer size). This will just about eliminate any temp file usage.

Hope this helps.
--
Dave Wickert [MSFT]
dwickert (AT) online (DOT) microsoft.com
Program Manager
BI SystemsTeam
SQL BI Product Unit (Analysis Services)
--
This posting is provided "AS IS" with no warranties, and confers no rights.

"Reece" <reece_mitchell (AT) hotmail (DOT) com> wrote