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Diffstat (limited to 'Documentation/networking/bonding.txt')
| -rw-r--r-- | Documentation/networking/bonding.txt | 84 |
1 files changed, 82 insertions, 2 deletions
diff --git a/Documentation/networking/bonding.txt b/Documentation/networking/bonding.txt index 61f516b135b..d0914781830 100644 --- a/Documentation/networking/bonding.txt +++ b/Documentation/networking/bonding.txt @@ -49,6 +49,7 @@ Table of Contents 3.3 Configuring Bonding Manually with Ifenslave 3.3.1 Configuring Multiple Bonds Manually 3.4 Configuring Bonding Manually via Sysfs +3.5 Overriding Configuration for Special Cases 4. Querying Bonding Configuration 4.1 Bonding Configuration @@ -1318,8 +1319,87 @@ echo 2000 > /sys/class/net/bond1/bonding/arp_interval echo +eth2 > /sys/class/net/bond1/bonding/slaves echo +eth3 > /sys/class/net/bond1/bonding/slaves - -4. Querying Bonding Configuration +3.5 Overriding Configuration for Special Cases +---------------------------------------------- +When using the bonding driver, the physical port which transmits a frame is +typically selected by the bonding driver, and is not relevant to the user or +system administrator. The output port is simply selected using the policies of +the selected bonding mode. On occasion however, it is helpful to direct certain +classes of traffic to certain physical interfaces on output to implement +slightly more complex policies. For example, to reach a web server over a +bonded interface in which eth0 connects to a private network, while eth1 +connects via a public network, it may be desirous to bias the bond to send said +traffic over eth0 first, using eth1 only as a fall back, while all other traffic +can safely be sent over either interface. Such configurations may be achieved +using the traffic control utilities inherent in linux. + +By default the bonding driver is multiqueue aware and 16 queues are created +when the driver initializes (see Documentation/networking/multiqueue.txt +for details). If more or less queues are desired the module parameter +tx_queues can be used to change this value. There is no sysfs parameter +available as the allocation is done at module init time. + +The output of the file /proc/net/bonding/bondX has changed so the output Queue +ID is now printed for each slave: + +Bonding Mode: fault-tolerance (active-backup) +Primary Slave: None +Currently Active Slave: eth0 +MII Status: up +MII Polling Interval (ms): 0 +Up Delay (ms): 0 +Down Delay (ms): 0 + +Slave Interface: eth0 +MII Status: up +Link Failure Count: 0 +Permanent HW addr: 00:1a:a0:12:8f:cb +Slave queue ID: 0 + +Slave Interface: eth1 +MII Status: up +Link Failure Count: 0 +Permanent HW addr: 00:1a:a0:12:8f:cc +Slave queue ID: 2 + +The queue_id for a slave can be set using the command: + +# echo "eth1:2" > /sys/class/net/bond0/bonding/queue_id + +Any interface that needs a queue_id set should set it with multiple calls +like the one above until proper priorities are set for all interfaces. On +distributions that allow configuration via initscripts, multiple 'queue_id' +arguments can be added to BONDING_OPTS to set all needed slave queues. + +These queue id's can be used in conjunction with the tc utility to configure +a multiqueue qdisc and filters to bias certain traffic to transmit on certain +slave devices. For instance, say we wanted, in the above configuration to +force all traffic bound to 192.168.1.100 to use eth1 in the bond as its output +device. The following commands would accomplish this: + +# tc qdisc add dev bond0 handle 1 root multiq + +# tc filter add dev bond0 protocol ip parent 1: prio 1 u32 match ip dst \ + 192.168.1.100 action skbedit queue_mapping 2 + +These commands tell the kernel to attach a multiqueue queue discipline to the +bond0 interface and filter traffic enqueued to it, such that packets with a dst +ip of 192.168.1.100 have their output queue mapping value overwritten to 2. +This value is then passed into the driver, causing the normal output path +selection policy to be overridden, selecting instead qid 2, which maps to eth1. + +Note that qid values begin at 1. Qid 0 is reserved to initiate to the driver +that normal output policy selection should take place. One benefit to simply +leaving the qid for a slave to 0 is the multiqueue awareness in the bonding +driver that is now present. This awareness allows tc filters to be placed on +slave devices as well as bond devices and the bonding driver will simply act as +a pass-through for selecting output queues on the slave device rather than +output port selection. + +This feature first appeared in bonding driver version 3.7.0 and support for +output slave selection was limited to round-robin and active-backup modes. + +4 Querying Bonding Configuration ================================= 4.1 Bonding Configuration |