Dual Interfaces, Load Balancing, and Device Names
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-i idle-thresh
Maximum number of I/Os that can be outstanding to a
LUN and have the LUN still be considered idle. Used to
determine cache flush start time. Legal values are any
number greater than or equal to 0.
-t idle-delay-time Amount of time in 100-ms intervals that a unit must be
below idle-thresh to be considered idle. Once a unit is
considered idle, any dirty pages in the cache can begin idle
time flushing. Legal values are any number greater than or
equal to 0.
-w write-aside
The smallest write request size, in blocks, that will bypass
the cache and go directly to the disks. Legal values are any
number greater than or equal to 0.
The following example changes LUN 3 to perform write caching and rebuild
in four hours; it does not change the default owner.
raid5 -d sc4d2l0 chglun -l 3 -c write -d 0 -r 4
There is no output for the chglun parameter. Errors are printed to stderr.
Dual Interfaces, Load Balancing, and Device Names
If your storage system has two SPs (split-bus, dual-bus/dual-initiator, or
dual-interface/dual-processor), you can choose which disks to bind on each
SP. This flexibility lets you balance the load on your SCSI-2 interfaces and
SPs.
The SP on which you bind a physical disk unit is its default owner. The route
through the SP that owns a physical disk unit is the primary route to the disk
unit, and determines the device name of the disk unit. The route through the
other SP is the secondary route to the disk unit.
When the storage system is running, you change the primary route to a
physical disk unit by transferring ownership of the physical disk unit from
one SP to another. The change in ownership and the new route take effect at
the next power-on.
