Re: vm philosophising

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2002-01-18T15:53:12Z

On Fri, 18 Jan 2002, Tommy Faasen wrote:

> I have no clue about VM's but I can imagine that for example the following situations have different requirements:
> 1-Desktop: many "small" apps, I believe exe's remain in memory and data is written to disk? Anyway I can imagine fragmentation and latency is an issue here.
> 2-DBMS: 1 or 2 big programs which sometimes even do their own memory management.Fragmentation and latency isn't issue here I think however moving ltos of data to and from swap is.
> 3-Webserver: for example apache with many childs being created under high load and killed under low load. The data is always small (in case of static pages). So a lot of small swaps? Latency is not as much as un issue but I can imagine that fragmentation can be an issue?

There is another situation to consider which I think more typical in the
"Real World"

4 - The Typical Web server Environment, in many many companies that I have
seen.
The machine runs both the DBMS(mysql, Oracle, etc) and the web server
Apache. Therefore a balence of memory use needs to be struck between the
two applications. Then ususally the system also has a development
environment at the ready incase changes need to be made quickly from the
console. While this may not be true as things scale up for a business and
functions get separated to different machines. Many startups and small
businesses that I have worked with that have turned to LINUX for the OS
becuase the TCO, it offers over the other guys, tend to have just that
single does everything box.

-Bill