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OS Configuration

This section contains information on critical OS tuning items. More detailed tuning information can be found in the section on Performance Tuning.

FreeBSD Configuration

The standard FreeBSD 4.10+ kernel imposes a per-process limit of 512 MB of memory. This is not enough for most Bro installations. Unfortunately the only way to increase this limit is to rebuild the kernel.

To check your current limit, type:

     limits -H
     

and look at the datasize setting, which should be the same as your amount of RAM. If this is not true, see section Hardware and OS Tuning for information on fixing this.

For FreeBSD 5.3+, BPF devices are no longer created using MAKEDEV, but rather are created on demand if defined in /etc/devfs.conf. For example, add the following to /etc/devfs.conf, and reboot the system:

    perm    bpf0    0660
    own     bpf0    0:0
    perm    bpf1    0660
    own     bpf1    0:0
    .
    .
    .
    perm    bpf7    0660
    own     bpf7    0:0

NOTE: eventually this will be done automatically by 'make install'

Linux Configuration

increase these (need to get recommended values for these):

/proc/sys/net/core/rmem_default (IP-Stack socket receive queue)
/proc/sys/net/core/rmem_max     (similar to rmem_default)
/proc/sys/net/core/netdev_max_backlog (queue between driver and socket)