Le 05 octobre 2000 a 13:59, Yvonne Beever a écrit :
> Is there a reasonable limit to the amount of virtual hosts one should
> run on a server? For example, we're up to 5 virtual hosts on one web
> server (using Apache) and are considering adding another. One opinion
> has been voiced that the more you add, the easier it is for things to
> break.
You can theoretically have up to 256 virtual IP aliases on one network
interface with Linux. As long as your network can handle the load and
you have enough RAM, it should be ok.
> My boss also asked about the number of httpd daemons running...
> Someone here added more daemons to the server, he said, and he was
> wondering if there were limits...
This is an Apache tuning thing: it can be a difficult task! The first
point is, you will not want to swap. Ever. Or else, your server
"thrashes" and things get worse than ever. I thus suggest you put as
many RAM as you can, 512 Mb or even 1 Gb if you can afford it, depending
on the load you expect.
Then, you can increase the number of max servers, and almost every
parameter which looks like MaxSomething or MinOtherThing in the Apache
conf files, _except_ do not let MaxSpareServers grow too high (leave it
to 15 or 25, like the default). The reason : every time a request hits
your Apache server, every spare server waiting for a connection will
"wake up", then only one will actually serve the request and all the
rest will go to sleep. That means many, many context switches for just
one request. Now imagine there are 100 spare servers and you being hit
at ~ 100 hits / second: your web server is slow, even though you have
enough RAM and you do not swap.
olive
--
Olivier Tharan, <[EMAIL PROTECTED]>
SCCS, the source motel! Programs check in and never check out! - Ken
Thompson
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