[THIN] Re: Performance Issues - Off Topic

  • From: Adam_Baum@xxxxxxxxxxxxx
  • To: thin@xxxxxxxxxxxxx
  • Date: Thu, 10 Oct 2002 12:42:57 -0700

Time to chime in a bit...

In my environment, the results I have seen contradict some of what others
have said.   In dealing with SQL server, quad 900 Xeons beat out dual 2.4
non-Xeon based chips.  The larger onchip cache, pipelines, etc are are
exploited by Miscrosoft.  Most vendors don't handle the differences in chip
architectures well.

Now, once you start comparing apples to apples, if the application is
written for it, a quad is faster than a dual.  It's not a linear jump in
performance, but it should produce at least 40% more transactions.  It
again comes down to what architecture the application was written for.
Once you start in on the SMP systems, the app has to manage its own
threads.  Most programmers assume two chips, not four or more.

I agree on the disk issue.  Most people assume the CPU is at fault when it
is really the disk or network.  We have some people here complaining that a
brand new quad 1.6ghz is slow.  Turns out the all the users upgraded to
100Mbp on the desktop.  Some went so far as to get gig to the desktop (wish
my dept had that budget). The server was also at 100Mbps.  I connected to a
1Gb port on the switch and presto.  Users think I worked magic.


                    "Eugene Herman"                                             
                    <EHerman@xxxxxx       To:     <thin@xxxxxxxxxxxxx>          
                    lth.net>              cc:                                   
                    Sent by:              Subject:     [THIN] Re: Performance 
Issues - Off Topic               
                    09:41 AM                                                    
                    Please respond                                              
                    to thin                                                     

The issue  basically is which server(s) we should up grade to.
In the current environment - I believe it is a Proliant 8000 Quad =
something or other running under Nw4.11 with a Vinca fail over
We are hitting almost 80% or higher utilization so we are finally in =
upgrade design.

The good news is that as you suggest - we are getting a SAN (EMC something
or other)  which should definitely Help out on disk access.
My co-worker who is a Netware guy aske me about this because I am  NT/2000
 trained. We both agree as do you that dual 2.4's chould be better than =
quad 900's and maybe even better than Quad 1600's. Problem is to convince =
managenemt that if you assume server life of 3 years before we upgrade - =
we could buy a heck of a lot of=20
new smaller boxes and upgrade lots of things as opposed to "outgrowing =
them" . besides in 3 yrs - they will probably have pentium 9's with 5 GB =
procesMHz and we would still be able to get much more life out of the 2.4 =
gb boxes


>>> djn@xxxxxxxxxxxxxxxxxx 10/10/02 11:38AM >>>

> Questions- if we compare the Dual 2.4 Xeon ML530 to the Quad DL760 with =
> 900 MHz processors - is there really more horsepower or does overhead =
> out any advantage of the quad processor.


> The basic question is - are there metrics to benchmark 2 vs 4 processor =
> systems

You need to focus on where the bottleneck is.  Have you or your vendor
conclusively proven that the bottleneck is the processors??  All too many
times, a vendor is willing to blame the hardware for their poorly written
software.  Most vendors are like lawyers -- if you see their lips are
moving, then you should be careful and suspect of their opinions!

IMHO, anything over 2 processors is a waste of time and money.  SMP only
scales well up to two processors -- after that, you've hit the point of
diminishing returns.  I have no hard metrics to prove it, but I can tell =
from experience that a dual 2.4 will run circles around a quad 900.

For servers that require high i/o (like database servers), I'd put your
money into the disk subsystem.  We use two external disk enclosures =
StorageWorks 4314 Ultra-3 SCSI) and a healthy sized RAID controller
(SmartArray 5300 w/256MB battery-backed cache).  The devices are configured

RAID 0+1 so we get the advantages of high disk i/o throughput and

Have you taken a good hard look at your disk subsystem?  Have you tuned it
as much as is possible?  That is, are the block sizes between your array
controller and OS the same?  Is your cache properly balanced?  In a Novell
environment, do you have at least 80% free memory available for file
caching?  What is your LRU sitting time?  etc etc etc

If you really need high-end processing power for your applications, you =
want to consider going to Unix.  Oh, I can hear the flames coming
already......    :)  Unix is geared specifically to handle
resource-intensive applications better than anything else out there.  =
Novell has a ton more configuration flexibility than Windows does, so I
don't know that I'd jump off that boat too quickly.

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