semi-custom kernel (was Re: PostgreSQL uses more memory on 6.1?)

Vivek Khera vivek at
Wed May 24 07:18:42 PDT 2006

On May 24, 2006, at 2:34 AM, Claus Guttesen wrote:

> Thank you. I wasn't aware that one could alter sysctl's. I might dive
> into that, makes kernel-maintenance a tiny bit easier.

Boy does it.  I've recently combined all my custom kernels into a  
single semi-custom configuration (actually two, one for SMP and one  
for UP) and adjust the sysctls either at sysctl.conf or at  
loader.conf depending on which needs to be where to adjust resources  
needed by certain servers.

For example, the DB servers I set the SHM and SEM settings, on the  
internal not-connected-to-internet boxes, I disable the firewall via  
sysctl, etc.

I also push into kld's the rarely used devices such as CD-ROM, floppy  
drive, USB keyboard, gmirror, which are used on only a handful of  
machines.  Then I load the ones I need via loader.conf so they are  
probed at boot.  The CDROM and floppy modules are loaded on demand  
(ie, basically never on a server)

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