SunOS man pages : in.mpathd (1)
Maintenance Commands in.mpathd(1M)
NAME
in.mpathd - daemon for network adapter (NIC) failure detec-
tion, recovery, automatic failover and failback
SYNOPSIS
/sbin/in.mpathd
DESCRIPTION
The in.mpathd daemon performs Network Interface Card (NIC)
failure and repair detection. In the event of a NIC failure,
it causes IP network access from the failed NIC to failover
to a standby NIC, if available, or to any another opera-
tional NIC that has been configured as part of the same net-
work multipathing group. Once the failed NIC is repaired,
all network access will be restored to the repaired NIC.
The in.mpathd daemon detects NIC failure and repair by send-
ing and receiving ICMP echo requests and replies on each
NIC. The in.mpathd daemon sends the probes to on-link
routers. If no routers are available, it sends the probes to
neighboring hosts. Thus, for network failure detection and
repair, there must be at least one neighbor on each link
that responds to ICMP echo request probes.
in.mpathd needs a special test address on each NIC for the
purpose of sending and receiving probes on each NIC. Use the
ifconfig command -failover option to configure these test
addresses. See ifconfig(1M). The test address must belong
to a subnet that is known to the hosts and routers on the
link.
in.mpathd works on both IPv4 and IPv6. If IPv4 is plumbed on
a NIC, an IPv4 test address is configured on theNIC, and the
NIC is configured as part of a network multipathing group,
then in.mpathd will start sending ICMP probes on the NIC
using IPv4.
In the case of IPv6, the link-local address must be config-
ured as the test address. The in.mpathd daemon will not
accept a non-link-local address as a test address. If the
NIC is part of a multipathing group, and the test address
has been configured, then in.mpathd will probe the NIC for
failures using IPv6.
Even if both the IPv4 and IPv6 protocol streams are plumbed,
it is sufficient to configure only one of the two, that is,
either an IPv4 test address or an IPv6 test address on a
NIC. If only an IPv4 test address is configured, it probes
using only ICMPv4. If only an IPv6 test address is config-
ured, it probes using only ICMPv6. If both type test
addresses are configured, it probes using both ICMPv4 and
ICMPv6.
SunOS 5.8 Last change: 3 Mar 2000 1
Maintenance Commands in.mpathd(1M)
The in.mpathd daemon accesses three variable values in
/etc/default/mpathd: FAILURE_DETECTION_TIME, FAILBACK and
TRACK_INTERFACES_ONLY_WITH_GROUPS.
The FAILURE_DETECTION_TIME variable specifies the NIC
failure detection time. The shorter the failure detection
time, the greater the volume of probe traffic. The default
value of FAILURE_DETECTION_TIME is 10 seconds. This means
that NIC failure will be detected by in.mpathd within 10
seconds. The NIC repair detection time cannot be configured;
however, it is defined as double the value of
FAILURE_DETECTION_TIME.
By default, in.mpathd does failure detection only on NICs
that are configured as part of a multipathing group. You can
set TRACK_INTERFACES_ONLY_WITH_GROUPS to no to enable
failure detection by in.mpathd on all NICs, even if they are
not part of a multipathing group. However, in.mpathd cannot
do failover from a failed NIC if it is not part of a mul-
tipathing group.
The in.mpathd daemon will restore network traffic back to
the previously failed NIC, after it has detected a NIC
repair. To disable this, set the value of FAILBACK to no in
/etc/default/mpathd.
FILES
/etc/default/mpathd
Contains default values used by the in.mpathd daemon.
ATTRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| Availability | SUNWcsr |
|_____________________________|_____________________________|
SEE ALSO
ifconfig(1M), attributes(5), icmp(7P), icmp6(7P),
System Administration Guide, Volume 3
DIAGNOSTICS
IFF_NOFAILOVER address
address is not unique and failure detection is not possible
Every test address that is configured must be
unique on the system. Otherwise in.mpathd cannot
SunOS 5.8 Last change: 3 Mar 2000 2
Maintenance Commands in.mpathd(1M)
do failure detection. Since the IPv6 test address
is a link-local address, which in turn is derived
from the ethernet address, each NIC must have a
unique MAC address.
NIC interface_name of group group_name is not plumbed
for IPv[4|6] and may affect failover capability
All NICs in a multipathing group must be homo-
geneously plumbed. For example, if a NIC is
plumbed for IPv4, then all NICs in the group must
be plumbed for IPv4. The streams modules pushed
on all NICs must be identical.
Failures cannot be detected on interface_name
as no IFF_NOFAILOVER address is available
Every NIC that is configured as part of a mul-
tipathing group must have a test address, which
can be either IPv4 or IPv6, or both. Otherwise
in.mpathd cannot probe the NIC, and this message
is displayed.
Invalid failure detection time assuming default 10000
An invalid value was encountered for
FAILURE_DETECTION_TIME in the /etc/default/mpathd
file.
Too small failure detection time of time
assuming minimum 100
The minimum value that can be specified for
FAILURE_DETECTION_TIME is currently 100 mil-
liseconds.
Invalid value for FAILBACK value
Valid values for the boolean variable FAILBACK
are yes or no.
Invalid value for TRACK_INTERFACES_ONLY_WITH_GROUPS value
Valid values for the boolean variable
TRACK_INTERFACES_ONLY_WITH_GROUPS are yes or no.
Cannot meet requested failure detection time of
time ms on (inet[4|6] interface_name)
new failure detection is time ms
The round trip time for ICMP probes is higher
than the specified failure detection time. The
network is probably congested or the probe tar-
gets are loaded. in.mpathd automatically
SunOS 5.8 Last change: 3 Mar 2000 3
Maintenance Commands in.mpathd(1M)
increases the failure detection time to whatever
it can achieve under these conditions.
Improved failure detection time time ms
The round trip time for ICMP probes has now
decreased and in.mpathd has lowered the failure
detection time correspondingly.
NIC failure detected on interface_name
in.mpathd has detected NIC failure on
interface_name, and has set the IFF_FAILED flag
on NIC interface_name.
Successfully failed over from NIC interface_name1 to
NIC interface_name2
in.mpathd has caused the network traffic to fail-
over from NIC interface_name1 to NIC
interface_name2, which is part of the multipath-
ing group.
NIC repair detected on interface_name
in.mpathd has detected that NIC interface_name is
repaired and operational. If the IFF_FAILED flag
on the NIC was previously set, it will be reset..
Successfully failed back to NIC interface_name
in.mpathd has restored network traffic back to
NIC interface_name, which is now repaired and
operational.
SunOS 5.8 Last change: 3 Mar 2000 4
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