Configure 10Gbps network capture

To ensure efficient data capture with minimal packet loss over high-volume 10Gb network interfaces, Splunk App for Stream lets you deploy an alternate Stream forwarder, which supports 10Gbps data capture on compatible network interfaces.

This page shows you how to optimize your Linux environment and configure Stream forwarder to enable 10Gbps data capture on compatible devices.

Operating system requirements

Dedicated 10Gb capture mode is supported on 64-bit Linux platforms (kernel version 2.6.32 or later). A variety of network devices are supported.

Note: Dedicated 10Gb capture mode has been tested on RHEL/CentOS only.

Optimize Linux environment

For best results with dedicated capture mode, update your kernel boot parameters for hugepages, as follows:

1. Edit /etc/grub.conf.
2. Add these parameters to your kernel boot line: default_hugepagesz=1G hugepagesz=1G hugepages=4. For example, after adding these parameters, your kernel boot line might look like this:

   kernel /vmlinuz-2.6.32-573.3.1.el6.x86_64 ro root=/dev/mapper/vg_cmload02-lv_root rd_LVM_LV=vg_cmload02/lv_root rd_NO_LUKS LANG=en_US.UTF-8 rd_NO_MD SYSFONT=latarcyrheb-sun16 crashkernel=auto rd_LVM_LV=vg_cmload02/lv_swap  KEYBOARDTYPE=pc KEYTABLE=us rd_NO_DM default_hugepagesz=1G hugepagesz=1G hugepages=4 rhgb quiet
   

3. Reboot your linux machine.

Note: Updating kernel boot parameters for dedicated capture mode is optional, though highly recommended.

Configure dedicated 10Gb capture mode

The following configuration steps apply to independent stream forwarder (streamfwd) deployments only. You must be a root user to run streamfwd in dedicated capture mode.

Step 1: Select streamfwd executable that supports 10Gb capture mode

Splunk App for Stream provides two different streamfwd executables: one which supports dedicated 10Gb capture mode and one which does not. The streamfwd executable that does not support dedicated 10Gb capture mode is chosen by default.

To select the streamfwd executable that supports dedicated capture mode, run set_capturemode.sh dedicated in the appropriate directory, depending on your stream forwarder deployment, as shown:

Splunk_TA_stream deployment

cd $SPLUNK_HOME/etc/apps/Splunk_TA_stream/
sudo ./set_capturemode.sh dedicated

Indpendent Stream forwarder deployment

cd /opt/streamfwd/scripts
sudo ./set_capturemode.sh dedicated

Step 2: Enable dedicated capture mode in streamfwd.conf

To enable dedicated capture mode, add dedicatedCaptureMode = 1 to your local/streamfwd.conf. For example:

[streamfwd]
port = 8889
ipAddr = 127.0.0.1
dedicatedCaptureMode = 1

Step 3: Identify compatible interfaces

You can select the dedicated capture mode compatible interfaces on which you want to capture 10Gbps traffic. To identify compatible interfaces, run bin/streamfwd --iflist. For example:

# ./bin/streamfwd --iflist
Dedicated capture mode compatible devices
=========================================
0000:04:00.0 driver=uio_pci_generic if=
0000:04:00.1 driver=uio_pci_generic if=
0000:05:00.0 driver=uio_pci_generic if=
0000:05:00.1 driver=uio_pci_generic if=

Dedicated capture mode non-compatible devices
=============================================
0000:02:00.0 driver=tg3 if=eth4 *Active*
0000:02:00.1 driver=tg3 if=eth5
0000:02:00.2 driver=tg3 if=eth6
0000:02:00.3 driver=tg3 if=eth7

You can capture packets at 10Gbps on any interface listed under Dedicated capture mode compatible devices.

Note: Dedicated capture mode compatible network interfaces use PCI bus addressing format.

Step 4: Specify network address in streamfwd.conf

In local/streamfwd.conf, specify the network address on which you want 10 Gbps capture to occur. For example:

[streamfwd]
port = 8889
ipAddr = 127.0.0.1
dedicatedCaptureMode = 1
streamfwdcapture.0.interface = 0000:04:00.0