Date: Tue, 25 Jul 2006 21:04:25 -0400 From: "Raymond Owens" <owensr@comcast.net> To: <freebsd-performance@freebsd.org> Subject: question concerning proper usage of kernel variables net.bpf.bufsize and vm_kmem_size_max Message-ID: <000701c6b04f$70c9b4d0$0501a8c0@desky64>
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This is a multi-part message in MIME format. ------=_NextPart_000_0003_01C6B02D.E94A5EE0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable System: Dell 2850 dual dual-core 3 Ghz Xeon processors FreeBSD 6.1 amd64=20 6Gb Ram Problem: System crashes when net.bpf.bufsize kernel variable is altered to value = above 67Mb Situation: Box performs packet capture using Bro IDS application. It was seen that = the larger the net.bpf.bufsize variable was made the more traffic that = was captured. Unfortunately when the net.bpf.bufsize and = net.bpf.maxbufsize variables exceed certain limits, the box immediately = crashes sometimes rebooting sometimes falling to single user mode. There = are a number of identical systems and the precise value at which this = crash occurs varies, one box crashes when the variable is set to over = 8Mb, others can be set successfully to 67Mb. Crash logs seem to = consistently give messages that 'kmem_map too small'. The = 'VM_KMEM_SIZE_MAX' variable is set by default apparently to 400Mb. Questions: Is there a limit to the value that net.bpf.bufsize and = net.bpf.maxbufsize can be set to? Is there a limit to the value that VM_KMEM_SIZE_MAX can be set to? Can VM_KMEM_SIZE_MAX be set manually with sysctl? Will increasing the value of VM_KMEM_SIZE_MAX have any chance of = preventing the crash? Thanks ------=_NextPart_000_0003_01C6B02D.E94A5EE0--
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