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2 <chapter xmlns="http://docbook.org/ns/docbook"
3 xmlns:xl="http://www.w3.org/1999/xlink" version="5.0" xml:lang="en-US"
4 xml:id="settingupbonding">
5 <title xml:id="settingupbonding.title">Setting Up Network Interface Bonding</title>
6 <para>This chapter describes how to use multiple network interfaces in parallel to increase bandwidth and/or redundancy. Topics include:</para>
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40 <para>Using network interface bonding is optional.</para>
42 <section xml:id="dbdoclet.50438258_95824">
43 <title>Network Interface Bonding Overview</title>
44 <para>Bonding, also known as link aggregation, trunking and port trunking, is a method of aggregating multiple physical network links into a single logical link for increased bandwidth.</para>
45 <para>Several different types of bonding are available in the Linux distribution. All these
46 types are referred to as 'modes', and use the bonding kernel module.</para>
47 <para>Modes 0 to 3 allow load balancing and fault tolerance by using multiple interfaces. Mode 4 aggregates a group of interfaces into a single virtual interface where all members of the group share the same speed and duplex settings. This mode is described under IEEE spec 802.3ad, and it is referred to as either 'mode 4' or '802.3ad.'</para>
49 <section xml:id="dbdoclet.50438258_29107">
50 <title>Requirements</title>
51 <para>The most basic requirement for successful bonding is that both endpoints of the connection must be capable of bonding. In a normal case, the non-server endpoint is a switch. (Two systems connected via crossover cables can also use bonding.) Any switch used must explicitly handle 802.3ad Dynamic Link Aggregation.</para>
52 <para>The kernel must also be configured with bonding. All supported Lustre kernels have bonding functionality. The network driver for the interfaces to be bonded must have the ethtool functionality to determine slave speed and duplex settings. All recent network drivers implement it.</para>
53 <para>To verify that your interface works with ethtool, run:</para>
54 <screen># which ethtool
59 Supported ports: [ TP MII ]
60 Supported link modes: 10baseT/Half 10baseT/Full
61 100baseT/Half 100baseT/Full
62 Supports auto-negotiation: Yes
63 Advertised link modes: 10baseT/Half 10baseT/Full
64 100baseT/Half 100baseT/Full
65 Advertised auto-negotiation: Yes
72 Supports Wake-on: pumbg
74 Current message level: 0x00000001 (1)
80 Supported ports: [ TP MII ]
81 Supported link modes: 10baseT/Half 10baseT/Full
82 100baseT/Half 100baseT/Full
83 Supports auto-negotiation: Yes
84 Advertised link modes: 10baseT/Half 10baseT/Full
85 100baseT/Half 100baseT/Full
86 Advertised auto-negotiation: Yes
93 Supports Wake-on: pumbg
95 Current message level: 0x00000007 (7)
97 To quickly check whether your kernel supports bonding, run:
98 # grep ifenslave /sbin/ifup
103 <section xml:id="dbdoclet.50438258_25353">
104 <title>Bonding Module Parameters</title>
105 <para>Bonding module parameters control various aspects of bonding.</para>
106 <para>Outgoing traffic is mapped across the slave interfaces according to the transmit hash
107 policy. We recommend that you set the <literal>xmit_hash_policy</literal> option to the
108 layer3+4 option for bonding. This policy uses upper layer protocol information if available to
109 generate the hash. This allows traffic to a particular network peer to span multiple slaves,
110 although a single connection does not span multiple slaves.</para>
111 <screen>$ xmit_hash_policy=layer3+4</screen>
112 <para>The <literal>miimon</literal> option enables users to monitor the link status. (The
113 parameter is a time interval in milliseconds.) It makes an interface failure transparent to
114 avoid serious network degradation during link failures. A reasonable default setting is 100
115 milliseconds; run:</para>
116 <screen>$ miimon=100</screen>
117 <para>For a busy network, increase the timeout.</para>
119 <section xml:id="dbdoclet.50438258_26899">
120 <title>Setting Up Bonding</title>
121 <para>To set up bonding:</para>
124 <para>Create a virtual 'bond' interface by creating a configuration file:</para>
125 <screen># vi /etc/sysconfig/network-scripts/ifcfg-bond0</screen>
128 <para>Append the following lines to the file.</para>
130 IPADDR=192.168.10.79 # Use the free IP Address of your network
132 NETMASK=255.255.255.0
138 <para>Attach one or more slave interfaces to the bond interface. Modify the eth0 and eth1 configuration files (using a VI text editor).</para>
141 <para>Use the VI text editor to open the eth0 configuration file.</para>
142 <screen># vi /etc/sysconfig/network-scripts/ifcfg-eth0</screen>
145 <para>Modify/append the eth0 file as follows:</para>
151 BOOTPROTO=none</screen>
154 <para>Use the VI text editor to open the eth1 configuration file.</para>
155 <screen># vi /etc/sysconfig/network-scripts/ifcfg-eth1</screen>
158 <para>Modify/append the eth1 file as follows:</para>
170 <para>Set up the bond interface and its options in <literal>/etc/modprobe.d/bond.conf</literal>. Start the slave interfaces by your normal network method.</para>
171 <screen># vi /etc/modprobe.d/bond.conf
175 <para>Append the following lines to the file.</para>
176 <screen>alias bond0 bonding
177 options bond0 mode=balance-alb miimon=100
181 <para>Load the bonding module.</para>
182 <screen># modprobe bonding
184 # ifenslave bond0 eth0 eth1
190 <para>Start/restart the slave interfaces (using your normal network method).</para>
192 <para>You must <literal>modprobe</literal> the bonding module for each bonded interface. If you wish to create bond0 and bond1, two entries in <literal>bond.conf</literal> file are required.</para>
194 <para>The examples below are from systems running Red Hat Enterprise Linux. For setup use:
195 <literal>/etc/sysconfig/networking-scripts/ifcfg-*</literal> The website referenced
196 below includes detailed instructions for other configuration methods, instructions to use
197 DHCP with bonding, and other setup details. We strongly recommend you use this
199 <para><link xl:href="http://www.linuxfoundation.org/collaborate/workgroups/networking/bonding">http://www.linuxfoundation.org/collaborate/workgroups/networking/bonding</link></para>
202 <para>Check /proc/net/bonding to determine status on bonding. There should be a file there for each bond interface.</para>
203 <screen># cat /proc/net/bonding/bond0
204 Ethernet Channel Bonding Driver: v3.0.3 (March 23, 2006)
206 Bonding Mode: load balancing (round-robin)
208 MII Polling Interval (ms): 0
212 Slave Interface: eth0
214 Link Failure Count: 0
215 Permanent HW addr: 4c:00:10:ac:61:e0
217 Slave Interface: eth1
219 Link Failure Count: 0
220 Permanent HW addr: 00:14:2a:7c:40:1d
224 <para>Use ethtool or ifconfig to check the interface state. ifconfig lists the first bonded interface as 'bond0.'</para>
226 bond0 Link encap:Ethernet HWaddr 4C:00:10:AC:61:E0
227 inet addr:192.168.10.79 Bcast:192.168.10.255 \ Mask:255.255.255.0
228 inet6 addr: fe80::4e00:10ff:feac:61e0/64 Scope:Link
229 UP BROADCAST RUNNING MASTER MULTICAST MTU:1500 Metric:1
230 RX packets:3091 errors:0 dropped:0 overruns:0 frame:0
231 TX packets:880 errors:0 dropped:0 overruns:0 carrier:0
232 collisions:0 txqueuelen:0
233 RX bytes:314203 (306.8 KiB) TX bytes:129834 (126.7 KiB)
235 eth0 Link encap:Ethernet HWaddr 4C:00:10:AC:61:E0
236 inet6 addr: fe80::4e00:10ff:feac:61e0/64 Scope:Link
237 UP BROADCAST RUNNING SLAVE MULTICAST MTU:1500 Metric:1
238 RX packets:1581 errors:0 dropped:0 overruns:0 frame:0
239 TX packets:448 errors:0 dropped:0 overruns:0 carrier:0
240 collisions:0 txqueuelen:1000
241 RX bytes:162084 (158.2 KiB) TX bytes:67245 (65.6 KiB)
242 Interrupt:193 Base address:0x8c00
244 eth1 Link encap:Ethernet HWaddr 4C:00:10:AC:61:E0
245 inet6 addr: fe80::4e00:10ff:feac:61e0/64 Scope:Link
246 UP BROADCAST RUNNING SLAVE MULTICAST MTU:1500 Metric:1
247 RX packets:1513 errors:0 dropped:0 overruns:0 frame:0
248 TX packets:444 errors:0 dropped:0 overruns:0 carrier:0
249 collisions:0 txqueuelen:1000
250 RX bytes:152299 (148.7 KiB) TX bytes:64517 (63.0 KiB)
251 Interrupt:185 Base address:0x6000
256 <title>Examples</title>
257 <para>This is an example showing <literal>bond.conf</literal> entries for bonding Ethernet interfaces <literal>eth1</literal> and <literal>eth2</literal> to <literal>bond0</literal>:</para>
258 <screen># cat /etc/modprobe.d/bond.conf
262 options bond0 mode=balance-alb miimon=100
264 # cat /etc/sysconfig/network-scripts/ifcfg-bond0
267 NETMASK=255.255.255.0
268 IPADDR=192.168.10.79 # (Assign here the IP of the bonded interface.)
273 # cat /etc/sysconfig/network-scripts/ifcfg-eth0
276 HWADDR=4c:00:10:ac:61:e0
285 <para>In the following example, the <literal>bond0</literal> interface is the master (MASTER) while <literal>eth0</literal> and <literal>eth1</literal> are slaves (SLAVE).</para>
287 <para>All slaves of <literal>bond0</literal> have the same MAC address (Hwaddr) - <literal>bond0</literal>. All modes, except TLB and ALB, have this MAC address. TLB and ALB require a unique MAC address for each slave.</para>
289 <screen>$ /sbin/ifconfig
291 bond0Link encap:EthernetHwaddr 00:C0:F0:1F:37:B4
292 inet addr:XXX.XXX.XXX.YYY Bcast:XXX.XXX.XXX.255 Mask:255.255.252.0
293 UP BROADCAST RUNNING MASTER MULTICAST MTU:1500 Metric:1
294 RX packets:7224794 errors:0 dropped:0 overruns:0 frame:0
295 TX packets:3286647 errors:1 dropped:0 overruns:1 carrier:0
296 collisions:0 txqueuelen:0
298 eth0Link encap:EthernetHwaddr 00:C0:F0:1F:37:B4
299 inet addr:XXX.XXX.XXX.YYY Bcast:XXX.XXX.XXX.255 Mask:255.255.252.0
300 UP BROADCAST RUNNING SLAVE MULTICAST MTU:1500 Metric:1
301 RX packets:3573025 errors:0 dropped:0 overruns:0 frame:0
302 TX packets:1643167 errors:1 dropped:0 overruns:1 carrier:0
303 collisions:0 txqueuelen:100
304 Interrupt:10 Base address:0x1080
306 eth1Link encap:EthernetHwaddr 00:C0:F0:1F:37:B4
307 inet addr:XXX.XXX.XXX.YYY Bcast:XXX.XXX.XXX.255 Mask:255.255.252.0
308 UP BROADCAST RUNNING SLAVE MULTICAST MTU:1500 Metric:1
309 RX packets:3651769 errors:0 dropped:0 overruns:0 frame:0
310 TX packets:1643480 errors:0 dropped:0 overruns:0 carrier:0
311 collisions:0 txqueuelen:100
312 Interrupt:9 Base address:0x1400</screen>
315 <section xml:id="dbdoclet.50438258_54769">
316 <title>Configuring a Lustre File System with Bonding</title>
317 <para>The Lustre software uses the IP address of the bonded interfaces and requires no special
318 configuration. The bonded interface is treated as a regular TCP/IP interface. If needed,
319 specify <literal>bond0</literal> using the Lustre <literal>networks</literal> parameter in
320 <literal>/etc/modprobe</literal>.</para>
321 <screen>options lnet networks=tcp(bond0)</screen>
323 <section xml:id="dbdoclet.50438258_92244">
324 <title>Bonding References</title>
325 <para>We recommend the following bonding references:</para>
328 <para>In the Linux kernel source tree, see
329 <literal>documentation/networking/bonding.txt</literal></para>
332 <para><link xl:href="http://linux-ip.net/html/ether-bonding.html"
333 >http://linux-ip.net/html/ether-bonding.html</link>.</para>
336 <para><link xl:href="http://www.sourceforge.net/projects/bonding"
337 >http://www.sourceforge.net/projects/bonding</link>.</para>
340 <para>Linux Foundation bonding website: <link
341 xl:href="http://www.linuxfoundation.org/collaborate/workgroups/networking/bonding"
342 >http://www.linuxfoundation.org/collaborate/workgroups/networking/bonding</link>. This
343 is the most extensive reference and we highly recommend it. This website includes
344 explanations of more complicated setups, including the use of DHCP with bonding.</para>
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