Date: Fri, 10 Apr 2009 14:23:23 -0700 From: Kip Macy <kmacy@freebsd.org> To: Freddie Cash <fjwcash@gmail.com> Cc: freebsd-stable@freebsd.org Subject: Re: Network sysctl tuning [was Re: ZFSKnownProblems - needs revision?] Message-ID: <3c1674c90904101423v68d1bb42q5b4ab510cc4cda1d@mail.gmail.com> In-Reply-To: <b269bc570904091542gce3c7a1v40afa0bb8e5ecb9e@mail.gmail.com> References: <gri5d9$15l$1@ger.gmane.org> <200904080959.49201.fjwcash@gmail.com> <49DD2B44.5020808@mawer.org> <b269bc570904091542gce3c7a1v40afa0bb8e5ecb9e@mail.gmail.com>
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I think most if not all of the gains are from increasing the maximum tcp socket buffer sizes. You might test it out with only those to confirm. -Kip On Thu, Apr 9, 2009 at 3:42 PM, Freddie Cash <fjwcash@gmail.com> wrote: > On Wed, Apr 8, 2009 at 3:55 PM, Antony Mawer <fbsd-stable@mawer.org> wrote: >> Freddie Cash wrote: >> ... >>> We've also heavily modified /etc/sysctl.conf and upped a bunch of the >>> network-related sysctls. Doing so increased our SSH throughput from ~30 >>> Mbits/sec across all connections to over 90 Mbits/sec per SSH connection. >> >> Are you able to share any of these with the list? It would be useful to >> compare as a lot of these tunings people do individually and it would be >> good to allow others to test in their environments to see if they help, as >> well as potentially adding them to the tuning man-page. > > They're all taken from the HPN-SSH website and various google searches > related to HPN-enabled OpenSSH. > > I don't know exactly what all the different, individual sysctls do, > nor whether this is the most optimal setup, but here's the sysctl.conf > that we use. This is on 2 systems using a quad-port gigabit NIC where > the top two ports are connected via lagg(4) and the bottom two ports > are connected via lagg(4), with the two laggX interfaces on separate > networks. > > I did a bunch of scp/sftp transfers of 100 MB files filled with random > data pulled from /dev/random between these two boxes tweaking the > options one at a time, but didn't do too much in the way of > scientific/empirical measurements and comparisons beyond the > throughput data that scp/sftp shows. > > If there are any glaring errors, gotchas, or "why would you ever do > that"s, let me know. :) > > # General network settings > net.isr.direct=1 # Whether to enable Direct > Dispatch for netisr > > > # IP options > net.inet.ip.forwarding=0 # Whether to enable packet > forwarding for NAT/routing > net.inet.ip.process_options=0 # Disable processing of IP > options (nothing uses this field) > net.inet.ip.random_id=1 # Randomise the IP header ID number > net.inet.ip.redirect=0 # Whether to allow redirect packets > #net.inet.ip.stealth=0 # Whether to appear in traceroute output > > > # ICMP options > net.inet.icmp.icmplim=200 # Limit ICMP packets to this > many per second > net.inet.icmp.drop_redirect=1 # Drop ICMP redirect packets > net.inet.icmp.log_redirect=0 # Don't log ICMP redirect packets > > > # TCP options > net.inet.tcp.blackhole=1 # Drop packets destined to unused ports > net.inet.tcp.inflight.enable=0 # Use automatic TCP window-scaling > net.inet.tcp.log_in_vain=0 # Don't log the blackholed packets > net.inet.tcp.path_mtu_discovery=1 # Use ICMP type 3 to find the MTU to use > net.inet.tcp.recvbuf_max=16777216 # The max size of the receive > buffer (16 MB) > net.inet.tcp.recvspace=131072 # The initial size in bytes of > the receive buffer > net.inet.tcp.sack.enable=1 # Enable Selective ACKs > net.inet.tcp.sendbuf_max=16777216 # The max size of the send buffer > net.inet.tcp.sendspace=131072 # The initial size in bytes of > the send buffer > net.inet.tcp.syncookies=1 # Enable SYN cookie protection > net.inet.tcp.rfc1323=1 # Enable RFC1323 extensions > (TCP window scaling) > > > # UDP options > net.inet.udp.blackhole=1 # Drop packets destined to unused ports > net.inet.udp.checksum=1 # Enable UDP checksums > net.inet.udp.log_in_vain=0 # Don't log the blackholed packets > net.inet.udp.recvspace=65536 # Size in bytes of the receive buffer > > > # Debug options > debug.minidump=1 # Disable the small kernel > core dump (only mem in use) > debug.mpsafevfs=1 # Enable threaded VFS subsystem > > > # Kernel options > kern.coredump=0 # Disable kernel core dumps > kern.ipc.maxsockbuf=4194304 # Set the max size of the > socket buffers (4 MB) > kern.ipc.somaxconn=1024 # Expand the IP listen queue > kern.maxvnodes=250000 # Bump up the max number of vnodes > > > # PCI bus options > hw.pci.enable_msix=1 # Enable Message Signalled > Interrupts - Extended > hw.pci.enable_msi=1 # Enable Message Signalled Interrupts > hw.pci.enable_io_modes=1 # Enable alternate I/O access modes > > -- > Freddie Cash > fjwcash@gmail.com > _______________________________________________ > freebsd-stable@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-stable > To unsubscribe, send any mail to "freebsd-stable-unsubscribe@freebsd.org" > -- All that is necessary for the triumph of evil is that good men do nothing. Edmund Burke
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