Hello all,

After 2-3 months of digging I solved my problem through deduction.

Turns out this issue is a MS NT issue, possibly SP6 related.

Given:
-----------------
slow bursty IIS download, ok at times, extremely slow at other times
typically when multiple processes (PHP, ASP, or others are executing)

A system with multiple disks & multiple pagefile.sys swap partitions

  Our NT configuration consisted of 2 SCSI controllers with 2+ disks.
  Drive C had a small (just big enough for memory) pagefile.sys of 400 MB
  Drive D had a large pagefile.sys 1000 MB
  Drive C was primary swap, with D secondary.

Problem Deduction:
---------------------------

When a NT box performs it's startup sequence a list of
processes are executed.  Each process initializes it's variables
requiring SWAP & MEMORY, and some are put to sleep
until they are needed.

The INETINFO (IIS) process is one of these.  It is initialized very
early in this process and appears to bind/use the pagefile.sys defined
on drive C:.

So, everything still cool.....

The "GOTCHA" is that inetinfo appears to not be able to use other
swap/partition areas on any drive other than C:  No matter how large
or amount of free swap space is left.

In our case, we watched as the swap space was eaten up to about 35%
(as it turned out this is the percentage space defined on drive C) and then the
problem would result.  Seeing lots-o-swap available caused us to look at other reasons
for the bursty behavior.

During the way-before-problem time there were articles in NT rags recommending
different ways to pre-define large contiguous SWAP areas to avoid fragmentation, and
to put a "realy-big" one on another SCSI controller & drive (other than C's) to speed
performance.  This is the way we have existed for many years.  Appears to NOT be
good advice for our situation.

This is a more global in scope that just our configuration.  During our trouble period
it became so slow that I rebuilt a NT Server from scratch, ported the code, and had the
same problem in the same % memory utilization as the other system.  This is a MS issue.

My problem was that the PHP CGI installer came out right around the same time
SP6a came out.  Don't know if this swap/pagefile issue is related to SP6, SP6a, but
we did not have the problem back in the SP3-5 days.....

Eric L. Edberg
Lucent Technologies
Network Engineering Manager
[EMAIL PROTECTED]


"Eric L.. Edberg" wrote:

> Hello all,
>
> I use NT IIS with SP6a to access an MS Access db using ODBC with
> ASP based scripts primarily, and have been writing new PHP4 where appropriate
> for the past year.
>
> I am using  PHP404pl1 CGI installer and have experienced a troublesome
> performance issues after executing PHP scripts (randomly it seems)
>
> The problem goes like this:
>
> *  ASP scripts execute ok for long periods of time
>
> *  A PHP script (which are seldom executed) appears to execute ok
>
> *  ASP scripts are then executed, but the download bitrate slows to a crawl,
>     sometime down to the 500b/s rate.  The scripts sometimes don't complete due
>     to timeout issues.
>
> * After approximately 5 minutes, all ASP scripts start working within expected and 
>normal
>    rates (50kb/s)
>
> There appears to be a contention or resource issue between ASP and PHP4.  The problem
> was not noticed when I was using PHP3.
>
> Our developers have monitored NT's memory, CPU, Pagefile utilization which are all 
>clean.
> We have looked at MS' IIS site for tuning hints and updated some parameters.
>
> Has anyone else experienced performance issues with IIS that affects the download 
>performance
> of html back to the desktop?
>
> Any IIS/Access experts willing to comment?
>
> Any know PHP4 bugs?
>
> Eric Edberg
> Network Engineering Manager
> Lucent Technologies
> 630-713-5231
> [EMAIL PROTECTED]
>
>   
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