Red Hat DEVICE-MAPPER MULTIPATH 4.6 Configuration And Administration Manual page 33

and
no_path_retry rr_min_io
If the device is active/passive, but it automatically switches paths with I/O to the passive path,
you need to change the checker function to one that does not send IO/ to the path to test if it is
working (otherwise, your device will keep failing over). This almost always means that you set
the to
path_checker tur
command, which most do.
If the device needs a special command to switch paths, then configuring this device for
multipath requires a hardware handler kernel module. The current hardware handlers are
and " . If these are not sufficient for your device, you may not be able to configure the
rdac
device for multipath.
Attribute
vendor
product
bl_product
path_grouping_policy
getuid_callout
prio_callout
path_checker
path_selector
failback
, as described in
; this works for all SCSI devices that support the Test Unit Ready
Description
Specifies the vendor name of the storage device to which the
attributes apply, for example
device
Specifies the product name of the storage device to which the
attributes apply, for example
device
Specifies a regular expression used to blacklist devices by
vendor/product. Note that for a device to get blacklisted, the
,
vendor product
Specifies the default path grouping policy to apply to
unspecified multipaths. Possible values include:
= 1 path per priority group
failover
= all valid paths in 1 priority group
multibus
group_by_serial
number
group_by_prio
group_by_node_name
Specifies the default program and arguments to call out to
obtain a unique path identifier. An absolute path is required.
Specifies the the default program and arguments to call out to
obtain a path weight. Weights are summed for each path
group to determine the next path group to use in case of
failue. "none" is a valid value.
Specifies the default method used to determine the state of
the paths. Possible values include
emc_clariion
Specifies the default algorithm to use in determining what
path to use for the next I/O operation.
Specifies path group failback.
A value of 0 or
path group whith a higher priority than the current path group
the system switches to that path group.
Configuration File Devices
Table 4.3, "Device Attributes".
, and strings must all match.
bl_product
= 1 priority group per detected serial
= 1 priority group per path priority value
= 1 priority group per target node name
readsector0
, , and
hp_sw directio
specifies that as soon as there is a
immediate
emc
.
COMPAQ
.
HSV110 (C)COMPAQ
and ,
tur
.
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