Date: Fri, 29 Sep 2006 11:58:25 -0400 From: John Nielsen <lists@jnielsen.net> To: freebsd-questions@freebsd.org Cc: Chris <snagit@cbpratt.prohosting.com> Subject: Re: Swap Size Importance? Message-ID: <200609291158.25518.lists@jnielsen.net> In-Reply-To: <BAB82621-2B6E-4D53-9B0B-C7158E945E95@cbpratt.prohosting.com> References: <BAB82621-2B6E-4D53-9B0B-C7158E945E95@cbpratt.prohosting.com>
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On Friday 29 September 2006 11:52, Chris wrote: > As a standard practice, I've always configured swap file to be double > the size of real ram split across system and data disk. For example, > 8gb on da0 and 8gb on da1 if the system has 8g real ram. In practice, > In 7 or 8 years, I've never seen swap used for anything but a few k > of inactive processes and I would imagine if real active process > swapping occurred, it would be an immediate indicator that the system > that isn't responsive enough for use anymore and requires upgrade or > tuning. Can't run a website process off disk and keep anyone coming > to the site ;-). (BTW, I'm talking only about high end servers, not > test boxes where I've seen lots of swapping). > > I'm at the point of attempting my first gvinum software raid-5 and > realized, I need the entire disk storage of all three non-system > drives to avoid pulling an 8gb chunk out of the drive sizes. The > configuration is one scsi 72g system disk and 3 that will be used for > the raid volume. I should mention I turn off dumps, haven't found the > use for that in a production server since it should not be rebooting > or it's back in the shop and another box is taking it's place. > > Is there any shortfall in performance or reliability to running > production with swap equal in size to the 8gb of system memory? I > can't think of any but don't want to make a hard to correct mistake > once this thing goes in. Nope. I routinely run boxes with 512MB or 1GB of swap, even if the RAM size is much higher than that. You won't have anywhere to save a crashdump in that case, but you seem to already be aware of that. JN
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