I have Sun with Quad Core Processor with 8GB of ram. I am running into performance isssues especially with people who are connecting remotely. It seems to be especially true for people who might not have great internet connections.
While they are having problems on Moodle, they are able to connect to other servers at the same location. Some will not be able to log in in the first place and others will be working and then freeze and and may or may not be requested to login. They will not be able to login. When the drops/freezes occur, the log files only show a few users, and running "top" on my server (UBUNTU 8.04) doesn't show any indication of resources being strained.
One area I am wondering about is my NICs, I have 4 of them (all on the same network segment) DNS for the site points to all 4 of them with the same name and different IP addresses. (ie. an "A" record for moodle.mydomain.edu xxx.xxx.xxx.10, and an "A" record for moodle.mydoman.edu xxx.xxx.xxx.11, ...) They are all Gigabit cards. Is there a need for multiple cards? I only have a 20MB pipe to the internet for the server, so clearly from the outside I couldn't begin to reach the capacity of even 1 card. I probably don't have over 20 or so internal users at any time, so even there I wouldn't think that I would be taxing a single NIC too heavily. Does having multiple cards buy me any additional capacity that I am not thinking of? My thought is to disable three of the cards and go with a single NIC. I do know that users get different IPs. The one time I experienced the problem, I started out with one IP address, then the problem occurred and when Moodle started again (about 5 minutes later), I had a different IP address.
I should add, that I don't have any layer 4 devices doing round robin pointing to a particular IP in order to do load balancing. Getting a different IP address is purely a function of the negotiation of DNS and the user.
According to the Moodle log file, I had fewer than 5 users on the system when the last people reported an issue and they weren't doing anything I would have thought would have stressed the system. At the same time they were experiencing an issue, I had another remote user that didn't have a problem.