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authorJay Vosburgh <fubar@us.ibm.com>2008-05-17 21:10:14 -0700
committerJeff Garzik <jgarzik@redhat.com>2008-05-22 06:34:29 -0400
commit3915c1e8634a321d9680e5cd80a53053b642dc0c (patch)
tree430b2168edbc7f6c4ba3698d261b8573b422658a /Documentation/networking/bonding.txt
parentb2220cad583c9b63e085476df448fa2aff5ea906 (diff)
downloadlinux-3915c1e8634a321d9680e5cd80a53053b642dc0c.tar.bz2
bonding: Add "follow" option to fail_over_mac
Add a "follow" selection for fail_over_mac. This option causes the MAC address to move from slave to slave as the active slave changes. This is in addition to the existing fail_over_mac option that causes the bond's MAC address to change during failover. This new option is useful for devices that cannot tolerate multiple ports using the same MAC address simultaneously, either because it confuses them or incurs a performance penalty (as is the case with some LPAR-aware multiport devices). Because the MAC of the bond itself does not change, the "follow" option is slightly more reliable during failover and doesn't change the MAC of the bond during operation. This patch requires a previous ARP monitor change to properly handle RTNL during failovers. Signed-off-by: Jay Vosburgh <fubar@us.ibm.com> Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Diffstat (limited to 'Documentation/networking/bonding.txt')
-rw-r--r--Documentation/networking/bonding.txt96
1 files changed, 67 insertions, 29 deletions
diff --git a/Documentation/networking/bonding.txt b/Documentation/networking/bonding.txt
index a0cda062bc33..8e6b8d3c7410 100644
--- a/Documentation/networking/bonding.txt
+++ b/Documentation/networking/bonding.txt
@@ -289,35 +289,73 @@ downdelay
fail_over_mac
Specifies whether active-backup mode should set all slaves to
- the same MAC address (the traditional behavior), or, when
- enabled, change the bond's MAC address when changing the
- active interface (i.e., fail over the MAC address itself).
-
- Fail over MAC is useful for devices that cannot ever alter
- their MAC address, or for devices that refuse incoming
- broadcasts with their own source MAC (which interferes with
- the ARP monitor).
-
- The down side of fail over MAC is that every device on the
- network must be updated via gratuitous ARP, vs. just updating
- a switch or set of switches (which often takes place for any
- traffic, not just ARP traffic, if the switch snoops incoming
- traffic to update its tables) for the traditional method. If
- the gratuitous ARP is lost, communication may be disrupted.
-
- When fail over MAC is used in conjuction with the mii monitor,
- devices which assert link up prior to being able to actually
- transmit and receive are particularly susecptible to loss of
- the gratuitous ARP, and an appropriate updelay setting may be
- required.
-
- A value of 0 disables fail over MAC, and is the default. A
- value of 1 enables fail over MAC. This option is enabled
- automatically if the first slave added cannot change its MAC
- address. This option may be modified via sysfs only when no
- slaves are present in the bond.
-
- This option was added in bonding version 3.2.0.
+ the same MAC address at enslavement (the traditional
+ behavior), or, when enabled, perform special handling of the
+ bond's MAC address in accordance with the selected policy.
+
+ Possible values are:
+
+ none or 0
+
+ This setting disables fail_over_mac, and causes
+ bonding to set all slaves of an active-backup bond to
+ the same MAC address at enslavement time. This is the
+ default.
+
+ active or 1
+
+ The "active" fail_over_mac policy indicates that the
+ MAC address of the bond should always be the MAC
+ address of the currently active slave. The MAC
+ address of the slaves is not changed; instead, the MAC
+ address of the bond changes during a failover.
+
+ This policy is useful for devices that cannot ever
+ alter their MAC address, or for devices that refuse
+ incoming broadcasts with their own source MAC (which
+ interferes with the ARP monitor).
+
+ The down side of this policy is that every device on
+ the network must be updated via gratuitous ARP,
+ vs. just updating a switch or set of switches (which
+ often takes place for any traffic, not just ARP
+ traffic, if the switch snoops incoming traffic to
+ update its tables) for the traditional method. If the
+ gratuitous ARP is lost, communication may be
+ disrupted.
+
+ When this policy is used in conjuction with the mii
+ monitor, devices which assert link up prior to being
+ able to actually transmit and receive are particularly
+ susecptible to loss of the gratuitous ARP, and an
+ appropriate updelay setting may be required.
+
+ follow or 2
+
+ The "follow" fail_over_mac policy causes the MAC
+ address of the bond to be selected normally (normally
+ the MAC address of the first slave added to the bond).
+ However, the second and subsequent slaves are not set
+ to this MAC address while they are in a backup role; a
+ slave is programmed with the bond's MAC address at
+ failover time (and the formerly active slave receives
+ the newly active slave's MAC address).
+
+ This policy is useful for multiport devices that
+ either become confused or incur a performance penalty
+ when multiple ports are programmed with the same MAC
+ address.
+
+
+ The default policy is none, unless the first slave cannot
+ change its MAC address, in which case the active policy is
+ selected by default.
+
+ This option may be modified via sysfs only when no slaves are
+ present in the bond.
+
+ This option was added in bonding version 3.2.0. The "follow"
+ policy was added in bonding version 3.3.0.
lacp_rate