Re: Apache2 Memory Usage
We're also running some installations our customer's own virtualised environments.
In one I'm working on at present, we're running moodle 2.1 with about 700 daily active users (sorry - no idea what the 'concurrency' is off-hand) on:
* 64 bit dual core VMWare vsphere machine
* 8GB RAM
* Debian Squeeze amd64 installation
* apache2
* apc
The box has a load average of < 0.3 at all times, and our apache2 threads seems to have a RES of between 15m and 77m at present. We have 400+ MB of RAM completely unused, and 7.3Gb in the cache. Only 680Gb is actively used.
Our databases are stored on a separate db server which is (unfortunately) virtualised.
Virtualisation shouldn't cause any major issues - though virtualising a database server isn't great.
Also, using a 64-bit installation won't use a significant amount more memory - it will likely have a slightly higher memory overhead but I believe that this is passed to the host, not the instance. Without a 64-bit system, and 64-bit kernel you won't be able to access beyond the first 3.6GB RAM (okay... you could be running big-mem, but the overheads are just as high, if not higher).
Andrew
In one I'm working on at present, we're running moodle 2.1 with about 700 daily active users (sorry - no idea what the 'concurrency' is off-hand) on:
* 64 bit dual core VMWare vsphere machine
* 8GB RAM
* Debian Squeeze amd64 installation
* apache2
* apc
The box has a load average of < 0.3 at all times, and our apache2 threads seems to have a RES of between 15m and 77m at present. We have 400+ MB of RAM completely unused, and 7.3Gb in the cache. Only 680Gb is actively used.
Our databases are stored on a separate db server which is (unfortunately) virtualised.
Virtualisation shouldn't cause any major issues - though virtualising a database server isn't great.
Also, using a 64-bit installation won't use a significant amount more memory - it will likely have a slightly higher memory overhead but I believe that this is passed to the host, not the instance. Without a 64-bit system, and 64-bit kernel you won't be able to access beyond the first 3.6GB RAM (okay... you could be running big-mem, but the overheads are just as high, if not higher).
Andrew