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na_priority - commands for managing priority resources.
priority command argument ...
The priority family of commands manages resouce policies
for the appliance. These policies are especially applicable
on a heavily loaded appliance where resources are limited.
Others, such as buffer cache policy, are also of
value in a more general environment.
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.
A default priority policy is also defined, used when a
volume does not have a specific policy assigned to it.
priority on | off
Globally enables or disables priority management on
the appliance. Use the priority show command to
display whether priority management is currently
enabled on the appliance. See also the subcommand
priority set enabled_components which allows
selected priority components to be active after
priority on is used.
Note: priority on must be used for priority policies
to be active.
priority set volume volname option=value [option=value
...]
The priority set volume command manages the priority
policy 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 priority policy 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 policy for the volume,
while still preserving custom values.
The 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. This option sets derived values
of scheduling (CPU), concurrent disk IO
limit and NVLOG usage for the volume, based
on the settings of other volumes in the
aggregate.
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 priority policy, which is applied to volumes
without any specific priority policy. 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 policy 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, the number of
disks in the enclosing aggregate for
the volume and the type of disk. The
value default restores the IO concurrency
to its initial default.
enabled_components
Sets the enabled priority components.
Only the specified components are activated.
Allowed values are all or cache.
The default is all.
Note: priority on must be used to activate
priority policies in general.
priority show
Display global priority setting options,
including whether or not priority is enabled.
priority show default [-v]
Display the default priority policy. The
default priority policy is used when no specific
priority policy 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 policy configuration for
volume volname. If no volume name is given
then the priority policy 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 policy information for the
volume named volname.
When a clustered system is in failover mode priority policy
is merged from both cluster nodes to form a combined
policy.
priority set volume prodvol level=high system=low
Set the priority scheduling policy for volume prod_vol
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 if priority
on has been previous issued.
priority delete volume prodvol
Delete any specific priority policy for volume
prodvol. In this case the default policy is
applied for the volume.
priority on
priority set enabled_components=cache
priority set volume logvol cache=reuse
Set the cache policy for logvol to not cache data.
Only the cache component of priority is enabled.
na_vol (1), na_snapmirror (1),
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