Return-Path: owner-new-httpd Received: by taz.hyperreal.com (8.6.12/8.6.5) id RAA07553; Mon, 26 Jun 1995 17:28:05 -0700 Received: from life.ai.mit.edu by taz.hyperreal.com (8.6.12/8.6.5) with SMTP id RAA07547; Mon, 26 Jun 1995 17:28:02 -0700 Received: from volterra (volterra.ai.mit.edu) by life.ai.mit.edu (4.1/AI-4.10) for new-httpd@hyperreal.com id AA12962; Mon, 26 Jun 95 20:27:53 EDT From: rst@ai.mit.edu (Robert S. Thau) Received: by volterra (4.1/AI-4.10) id AA03997; Mon, 26 Jun 95 20:27:51 EDT Date: Mon, 26 Jun 95 20:27:51 EDT Message-Id: <9506270027.AA03997@volterra> To: new-httpd@hyperreal.com Cc: new-httpd@hyperreal.com In-Reply-To: (drtr@ast.cam.ac.uk) Subject: Re: Apache 0.7: too many processes Sender: owner-new-httpd@apache.org Precedence: bulk Reply-To: new-httpd@apache.org Date: Mon, 26 Jun 95 15:29 BST From: drtr@ast.cam.ac.uk (David Robinson) Precedence: bulk Reply-To: new-httpd@hyperreal.com This would be a pretty major disincentive for a low-use site to run apache. Running tens of daemons is very wasteful on swap space and kernel resources, and will put off sys admins. Is that so? As you note immediately after saying this: But a 0.7 server with a small number of daemons (5, say) would probably provide an inferior service to a 0.6 server. All it would take is one netscape user to access a page with a few inline images, and your site is saturated. In other words, under peak conditions you *need* to be able to run tens of daemons simultaneously or performance will be terrible. What's more, since peaks may arise without warning, you need those swap space and kernel resources to be available to the web server all the time, even if there isn't an actual process pre-forked and serving as a placeholder. (In any case, the amount of resources actually consumed by having the pre-forked children around is not that great; my process pool currently averages about 300K/process for 20, or about 6 megabytes total (printout below) --- that's not much these days for a dedicated server. NB this is Shambhala, but I don't think whatever difference there is between it and 0.7.x is enough to make a major impact). BTW, I do think there's an issue which can reasonably be addressed here, which is trying to find the right value for StartServers adaptively, rather than making the webmaster guess. However, as the experience at Cardiff suggests, I think the main issue here is making sure that you have enough of them that they don't all get tied up talking to slow clients. At any rate, any strategy for adaptively adjusting child server lifetimes should probably keep that in mind, as well as the connection arrival rate... rst PS: as promised, here's ps alx output for my server pool (these processes have all been running since 3:00 AM, so I don't expect them to get much bigger than this): F UID PID PPID CP PRI NI SZ RSS WCHAN STAT TT TIME COMMAND 80488000 0 3623 1 6 5 0 104 0 child IW ? 0:00 ./shambhala 488001 8 5092 3623 0 1 0 360 496 socket S ? 2:55 ./shambhala 488001 8 5093 3623 1 1 0 276 400 socket S ? 3:10 ./shambhala 488000 8 5094 3623 0 1 0 324 0 socket IW ? 3:33 ./shambhala 488001 8 5095 3623 0 1 0 276 424 socket S ? 3:10 ./shambhala 488000 8 5096 3623 0 1 0 312 0 socket IW ? 2:48 ./shambhala 488001 8 5097 3623 2 1 0 300 468 socket S ? 3:13 ./shambhala 488001 8 5098 3623 0 1 0 312 464 socket S ? 2:47 ./shambhala 488001 8 5099 3623 1 1 0 324 476 socket S ? 3:01 ./shambhala 488000 8 5100 3623 0 1 0 336 0 socket IW ? 3:13 ./shambhala 488000 8 5101 3623 0 1 0 324 0 socket IW ? 2:40 ./shambhala 488001 8 5102 3623 0 1 0 276 468 socket S ? 3:03 ./shambhala 488001 8 5103 3623 4 1 0 312 488 socket S ? 3:01 ./shambhala 488001 8 5104 3623 1 1 0 352 488 socket S ? 3:00 ./shambhala 488001 8 5105 3623 0 1 0 308 76 socket S ? 3:13 ./shambhala 488000 8 5106 3623 1 1 0 300 0 socket IW ? 3:12 ./shambhala 488001 8 5107 3623 1 1 0 312 484 socket S ? 2:43 ./shambhala 488001 8 5108 3623 1 1 0 300 472 socket S ? 2:43 ./shambhala 488001 8 5109 3623 0 1 0 324 456 socket S ? 3:01 ./shambhala 488001 8 5110 3623 0 1 0 344 484 socket S ? 3:12 ./shambhala 488001 8 5111 3623 2 1 0 276 448 socket S ? 2:56 ./shambhala