Kernel - maxusers, NMBCLUSTERS etc.

Jack L. Stone jackstone at
Wed Aug 13 08:16:29 PDT 2003

At 03:55 PM 8.13.2003 +0100, Jez Hancock wrote:
>On Wed, Aug 13, 2003 at 10:46:59AM -0400, Grant Peel wrote:
>> 1. Does anyone use the maxusers=0 parm? If so is it safe, ie does it
>> dynamicly set maxusers on-the-fly, or does it only set at boot time
based on
>> the current number of users?
>Yes and Yes, the setting is assigned at boot time and depends on an
>algorithm which you can read about in tuning(7) IIRC.
>I would say give it a go and see how it fairs.  Check out sysctl -a for
>your current settings and see how it changes when you set MAXUSERS to 0.
>Also check out fstat(1) to see what open files you currently have and what
>is consuming your file descriptors - perhaps you can cut down the number
>of open files.

132 is WAY too low. And, yes if you set maxusers to zero, this will be set
by the system and will also change as and when it needs too. I have some
servers that shows in excess of 12000, and lowes is at about 8000 (8192).

You can always reset the maxfiles without a reboot via this command:
sysctl -w kern.maxfiles=8192

It can also be placed in the /boot/loader.conf and you don't have to change
the kernel right away.

That can hold you until you rebuild the kernel and reboot....

Best regards,
Jack L. Stone,

SageOne Net
jackstone at

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