> "Issam W. Alameh" wrote:
>
> > I am thinking of celeron 600 with 512MB ram, what such
> > machine can serve and what is the best way to configure
> > and start the database server..
>
> Funny idea, to use a *Celeron* with that much RAM. :-)
I would disagree a bit here. I have actually found Celerons to be quite
useful processors and offer tremendous price to performance compared to PII
and PIII's. Under typical server situations I belive you'd get better
performance with a PII/I as well you have the possibility to have multiple
CPU's.
But to Issam's actual question. First of all, depending on the type of
traffic and work you're putting the DB server under you could realize a
performance by separating the two components (PHP/Apache and MySQL).
a) Visit:
http://www.mysql.com/documentation/mysql/commented/manual.php?section=System
for an overview of performance hints that could make sense for you.
b) Further in is:
http://www.mysql.com/documentation/mysql/commented/manual.php?section=Server
_parameters
With this recommendation:
--- excerpt ---
If you have much memory (>=256M) and many tables and want maximum
performance with a moderate number of clients, you should use something like
this:
shell> safe_mysqld -O key_buffer=64M -O table_cache=256 \
-O sort_buffer=4M -O record_buffer=1M &
--- /excerpt ---
c) If you're going to have a high number of PHP <-> MySQL communications
then you should look at how you intend to connect the two boxes - 10MB
ethernet? - why not something faster to minimize server to server latency?
d) You may want to run two different MySQL servers - one on the web host
for things like Sessions and then one on your main DB server for things like
the application requests....
e) Use tools like "top" to see what sorts of performance you're getting.
Maybe your system is bound by some other factor than CPU. Memory and Disk
bounding of processes can be quite common.
f) You may find it is easier to just add a bit more memory and another disk
to current system to relieve I/O bounding.
Assessing and improving performance can be tricky business. It does not
always entail adding a new box or a new processor. Usually a firm
understanding of where the limitations of the system will make it easier to
improve it. If you had said "on my system mysqld is taking 20% of the CPU,
50% of the RAM and my hard drives are thrashing like mad" then you'd show a
greater understanding of potential areas for problems and make it easier to
address them.
I, personally, do not have great amounts of experience with MySQL
performance issues as of yet, but these comments do come from several years
of working with large databases powered by another software (and its not
Oracle ;-) and I belive them to be applicable here. I am often asked a
similar question by my clients.
Kindest regards,
Jay
