Novell LINUX ENTERPRISE SERVER 11 - STORAGE ADMINISTRATION GUIDE 2-23-2010, Руководство администратора, Страница: 63 / 140

Managing Multipath I/O for Devices 63
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path_grouping_policy Specifies the path grouping
policy for a multipath device
hosted by a given controller.
failover: One path is assigned per priority group
so that only one path at a time is used.
multibus: (Default) All valid paths are in one
priority group. Traffic is load-balanced across all
active paths in the group.
group_by_prio: One priority group exists for
each path priority value. Paths with the same
priority are in the same priority group. Priorities
are assigned by an external program.
group_by_serial: Paths are grouped by the
SCSI target serial number (controller node
WWN).
group_by_node_name: One priority group is
assigned per target node name. Target node
names are fetched in
/sys/class/
fc_transport/target*/node_name
.
path_checker Determines the state of the
path. directio: (Default in multipath-tools version
0.4.8 and later) Reads the first sector that has
direct I/O. This is useful for DASD devices. Logs
failure messages in
/var/log/messages
.
readsector0: (Default in multipath-tools
version 0.4.7 and earlier) Reads the first sector
of the device. Logs failure messages in
/var/
log/messages
.
tur: Issues a SCSI test unit ready command to
the device. This is the preferred setting if the
LUN supports it. The command does not fill up
/
var/log/messages
on failure with messages.
Some SAN vendors provide custom
path_checker options:
Š
emc_clariion: Queries the EMC Clariion
EVPD page 0xC0 to determine the path
state.
Š
hp_sw: Checks the path state (Up, Down,
or Ghost) for HP storage arrays with Active/
Standby firmware.
Š
rdac: Checks the path state for the LSI/
Engenio RDAC storage controller.
Multipath Attribute Description Values