System perforamance 4.x vs. 5.x and 6.x

Uwe Doering gemini at
Sun Feb 17 15:51:33 UTC 2008

Brett Bump wrote:
> On Fri, 15 Feb 2008, Uwe Doering wrote:
>> Have you tried sorting this list alphabetically?  Believe it or not,
>> when I tried to use Apache 1.3.x with PHP 5.2.x with extensions in
>> arbitrary order I got inexplicable crashes, too.
>> Now, of course it was just a coincidence that it worked for me after
>> sorting the extension list.  What this in fact points to is that the
>> order of extensions can be important in that list, for whatever reason.
>>   For me it worked after sorting the list, but YMMV.  Might be worth a
>> try, though.
> Ran it stock, sorted, read a thread a while back about someone who thought
> you should have mysql first, then imap, then blah blah blah, nothing made
> any difference.  The machine tends to always show about 98% memory used,
> although at any point in time 1/2 of that could be inact.

This is normal.  FreeBSD uses almost all RAM for caching purposes if it 
isn't needed otherwise.

> The malloc
> errors in the apache logs made me consider the idea of adding more memory
> to the box (but there are always pundits that say, "wow, more than 2g?").

As long as swap is barely touched (as I believe you stated in another 
mail) too little RAM is not your problem.

However, 'RAM' brings me to another possibility.  There have been 
reports in the past that certain BIOSes can cause some parts of the RAM 
to be uncached, which would result in anemic server performance under 
load.  You may want to check with

   memcontrol list

that all relevant memory regions are set to 'write-back'.  Note that 
regions not mentioned explicitly are normally dealt with by a catch-all 
line towards the end of the list.  IIRC, doing a BIOS upgrade usually 
fixed the problem, but that is of course not guaranteed.


Uwe Doering         |  EscapeBox - Managed On-Demand UNIX Servers
gemini at  |

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