Hello, Let me start with a short introduction since I am new to this list, and you know what to expect of me. I'am not new to linux, I have been using it as my desktop for over a year, but I am fairly new to handling a 30+ serverpark which will grow an estimated 3 times this year (thats if things are slow, and I am lucky ;), any hints on keeping things manageble are appreciated but thats maybe for a new discussion, if you have some good things please start a new discussion to keep things clear.
So far my introduction. I want to performance profile the servers, I want to know what causes bottlenecks, which php script is taking ages, why are we waiting for IO, which files are locked, what caused the lock, and which threads are waiting for what lock. Are we waiting for the network, is the network fast enough, is nfs being a pain? etc.. etc.. All questions i still cannot answer. i have been working with iostat, vmstat, ps, lsof. But they all seem to provide basic information, I am able to skim the surface of my problems, but am unable to find the details i need to locate the problem/cause. An example of what happend a few weeks back. Each webserver runs mysql, apache and php, and a couple of nfs mounts to put uploaded and rendered images. ones or twice a day some of these server 'locked up' unable to serve http requests (no it was nog maxClient),but if we would give them some peace then they recovered on there own. After some research we found out that there was a good amount of time spent waiting for I/O. a dozen orso apache threads had a flock status, but for which file's? and which script was running?. All information i was missing to pin point the problem. After a hunch we moved the image rendering to some dedicated servers, and this seemed to help, so we where lucky this time. But next time, new problems, new solution. And I hope you guys can help me with new tools, new idea's, new knowledge and a better understanding of whats server management/tweaking is about and how to do it. With regards, Jos houtman http://www.hyves.net/frm.php/58069/5mJl Have a look, invite your friends its only fun if you have a network -- [email protected] mailing list
