Note on setting higher mbuf and mbuf cluster limits

Matthew Dillon dillon at
Sun May 13 16:09:40 PDT 2007

    I've just committed a change to make the kern.ipc.nmbufs and
    kern.ipc.nmbclusters sysctl variables read-only.  These variables
    cannot be adjusted on a running system (like for a year or more now),
    they can ONLY be adjusted as boot-time tunables, i.e. via 

    Having the writable sysctls just made all the statistics programs,
    like netstat -m, report the modified values when the mbuf allocator
    was actually still using the original values.  The result: confusion
    when someone's network seems to stall out due to having many connections
    but netstat -m doesn't report any limits being hit.

					Matthew Dillon 
					<dillon at>

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