Date: Mon, 28 Jan 2002 19:58:28 -0500 From: Dylan Carlson <absinthe@pobox.com> To: "Forrest W. Christian" <forrestc@imach.com>, Troy Settle <troy@psknet.com> Cc: freebsd-isp@FreeBSD.ORG Subject: Re: Tuning a system... Message-ID: <E16VMbW-00047M-00@falcon.prod.itd.earthlink.net> In-Reply-To: <Pine.BSF.4.21.0201281655580.14872-100000@workhorse.iMach.com> References: <Pine.BSF.4.21.0201281655580.14872-100000@workhorse.iMach.com>
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On Monday 28 January 2002 19:11, Forrest W. Christian wrote: > On Mon, 28 Jan 2002, Troy Settle wrote: > > So... my question is, how can I tune my FreeBSD 4-STABLE boxes to run a > > little more stable? I intend to update soon, I've just been putting it > > off in favor of running my business. > > First of all, what do you have MAXUSERS set to in the config file? It > sounds like you have it set to a rediculously low (like the > default) value. > > I generally set it to 256 and forget it. Others might argue that a lower > value is better as you don't want to "waste" too much memory and that 256 > increases a lot of kernel parameters. I'd rather just set it and forget > it. I can't say I've needed more than the quantity set by 256. > > Beyond this, I highly recommend you look at man tuning. This has > everything you need to know in it about tuning, as a general rule. This is something of an opinion piece, but I think it perhaps it needs to be raised... I wonder how many of these things, with some work to the kernel, could be made dynamic? I know Solaris has moved in this direction with a lot of its internals... including allocation of swap space, which no longer has to follow that "2 x physical" sizing rule of thumb anymore. If you have, say, 4GB of RAM in the machine and will never use more than that for your applications, it's ridiculous to create an 8GB swap partition to satisfy the algorithms the VM uses to address memory. At 30,000 ft it seems silly that the kernel can't be smart enough to take memory and allocate more resource as it needs to automatically, although even in my ignorance I understand that it's far from trivial to implement. Culturally, I think some admins prefer a kernel with hard limits because they believe it makes the system more predictable when you can lock in limits on resources. If there has been some reluctance on the part of both Linux and FreeBSD camps to put that kind of kernel work in, I would suspect that's why. I'm of the school of thought that says you're likely to spend a lot more time making kernel adjustments, compiling and rebooting than you ever would trying to reason with a dynamic kernel or deal with memory shortages, especially with as cheap as RAM is now. </opine> -- Dylan Carlson [absinthe@pobox.com] To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-isp" in the body of the message
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