Date: Sat, 5 Apr 2003 01:49:03 -0800 (PST) From: Josh Brooks <user@mail.econolodgetulsa.com> To: freebsd-hackers@freebsd.org Subject: KVA suggestions on 4gig+2gig memory system ? Message-ID: <20030405011856.T11740-100000@mail.econolodgetulsa.com>
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Hello, I have a new system that has 4gigs of physical memory ... and I am concerned about running into problems due to running out of KVM. I am running FreeBSD 4.8, and in addition to 4gigs of ram, I have configured 2gigs of swap space. The system does not swap much at all, but I need it there just in case. I will be upping shm as follows for database use: options SHMSEG=256 options SEMMNI=384 options SEMMNU=256 options SEMMAP=256 options SEMMNS=512 options SHMMAXPGS=12288 options SHMMAX="(SHMMAXPGS*PAGE_SIZE+1)" and the system will be used as a large multiuser system with a lot of different processes running (1200-1600 processes) So my questions are: 1. Should I change the default value of KVA_PAGES ? I have another system running the same processes and same load as this one, and it does not specify any KVA_PAGES in the kernel config, so it is using the default value - and it works wonderfully. BUT, this other system has 3 physical + 2 swap, and not 4 physical. So will that extra gig of physical demand altering KVA_PAGES ? 2. If I should change it, suggestions ? The default is 260, and I believe 512 splits memory in half ... perhaps 512 is a good number ? 3. are there any other tunables to worry about ? I think the key here is that I am running wonderfully on the 3+2 system without any tunings for KVA, so I am just looking for advice on what the extra gig of physical does for me...it may be useful to mention that the original 3+2 system has 40% swap usage ... but maybe that doesn't matter. thanks!
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