Red Hat ENTERPRISE LINUX 5.1 DM MULTIPATH Configuration And Administration Manual

Configuration File Devices19Attribute Descriptionproduct Specifies the product name of the storage device to which thedevice attributes apply, for example HSV110 (C)COMPAQ.product_blacklist Specifies a regular expression used to blacklist devices byproduct.path_grouping_policy Specifies the default path grouping policy to apply to unspecifiedmultipaths. Possible values include:failover = 1 path per priority groupmultibus = all valid paths in 1 priority groupgroup_by_serial = 1 priority group per detected serial numbergroup_by_prio = 1 priority group per path priority valuegroup_by_node_name = 1 priority group per target node namegetuid_callout Specifies the default program and arguments to call out to obtain aunique path identifier. An absolute path is required.prio_callout Specifies the the default program and arguments to call out toobtain a path weight. Weights are summed for each path group todetermine the next path group to use in case of failue. "none" is avalid value.path_checker Specifies the default method used to determine the state ofthe paths. Possible values include readsector0 and tur,emc_clariion, hp_sw, and directio.path_selector Specifies the default algorithm to use in determining what path touse for the next I/O operation.failback Specifies path group failback.A value of 0 or immediate specifies that as soon as there is apath group whith a higher priority than the current path group thesystem switches to that path group.A numeric value greater than zero specifies deferred failback,expressed in seconds.A value of manual specifies that failback can happen only withoperator intervention.features The extra features of multipath devices. The only existingfeature is queue_if_no_path, which is the same as settingno_path_retry to queue.hardware_handler Specifies a module that will be used to perform hardware specificactions when switching path groups or handling I/O errors.Possible values include 0, 1 emc, and 1 rdac. The default valueis 0.rr_min_io Specifies the number of I/O requests to route to a path beforeswitching to the next path in the current path group. The defaultvalue is 1000.rr_weight If set to priorities, then instead of sending rr_min_iorequests to a path before calling selector to choose thenext path, the number of requests to send is determined byrr_min_io times the path's priority, as determined by theprio_callout program. Currently, there are priority callouts onlyfor devices that use the group_by_prio path grouping policy,