Administrators may set various priority policies, including the following:
The relative priority of work associated with a volume (see na_vol.1)
For a given volume, the relative priority of system-related operations (e.g. snapmirror transfers) compared to user-related operations.
The buffer cache policy to be used for a volume.
The amount of IO concurrency allowed, prioritizing blocking operations such as disk reads.
A default priority schedule is also defined, used when a volume does not have a specific schedule assigned to it.
Globally enables or disables priority scheduling on the appliance. Use the priority show command to display whether priority scheduling is currently enabled on the appliance.
priority set volume volname option=value [option=value ...]
The priority set volume command manages the scheduling priority for the volume volname. The following options may be specified:
service
Set the service for the volume to value,
which may be on or off. When first setting
the scheduling priority for a volume the
service is automatically set to on, unless
it is explicitly disabled by setting to off.
The off value may also be used subsequently
to disable the explicit scheduling policy
for the volume, while still preserving custom
values. The scheduling policy for the
volume may be permanently deleted using priority
delete volume.
level Set the priority level for operations sent to the volume when compared to other volumes. The value may be one of VeryHigh, High, Medium, Low or VeryLow. A volume with a higher priority level will receive more resources than a volume with lower resources.
system Set the relative priority for system related operations (such as snapmirror transfers) sent to the volume compared to user operations sent to the volume. The value may be one of VeryHigh, High, Medium, Low or VeryLow, or a numeric percentage from 1 to 100%.
cache Set the buffer cache policy to use for the volume. Legal values are keep, meaning try to cache buffers if possible; reuse, meaninng buffers may be immediately reused; and default, meaning that the system default policy should be used.
priority set default option=value [option=value ...]
The priority set default command manages the default scheduling priority, which is applied to volumes without any specific priority scheduling. The following options may be specified:
level Set the priority level for operations sent to the volume when compared to other volumes. The value may be one of VeryHigh, High, Medium, Low or VeryLow. A volume with a higher priority level will receive more resources than a volume with lower resources.
system Set the relative priority for system related operations (such as snapmirror transfers) sent to the volume compared to user operations sent to the volume. The value may be one of VeryHigh, High, Medium, Low or VeryLow, or a numeric percentage from 1 to 100%.
priority set option=value
Set global priority scheduling options. The following options may be set:
io_concurrency
Sets the limit on the average number of
concurrent suspended operations per
disk for each volume. The allowed number
of suspended operations for a specific
volume is determined by the IO
concurrency setting and the number of
disks in the enclosing aggregate for
the volume. The value default restores
the IO concurrency to its initial
default.
priority show
Display global priority setting options,
including whether or not priority scheduling
is enabled.
priority show default [-v]
Display the default priority scheduling configuration.
The default priority scheduling
configuration is used when no specific priority
schedule has been specified.
If the -v (verbose) option is used then more
detailed output will be shown.
priority show volume [-v] [volname]
Display the priority scheduling configuration
for volume volname. If no volume name is
given then the priority scheduling configurations
for all volumes are shown.
If the -v (verbose) option is used then more
detailed output will be shown for options
available at the current priority level.
priority delete volume volname
Delete priority scheduling information for the
volume named volname.
Set the priority schedule for volume prodvol to high compared to other volumes. Also prioritize system operations for the volume low compared to user operations on the same volume. These options are also enabled by this operation.
priority delete volume prodvol
Delete any specific priority policy for volume prodvol. In this case the default policy is applied for the volume.
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