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ZFS Adaptive Replacement Cache

ZFS Adaptive Replacement Cache

Plugin: proc.plugin Module: /proc/spl/kstat/zfs/arcstats


This integration monitors ZFS Adadptive Replacement Cache (ARC) statistics.

This collector is supported on all platforms.

This collector supports collecting metrics from multiple instances of this integration, including remote instances.

Default Behavior


This integration doesn’t support auto-detection.


The default configuration for this integration does not impose any limits on data collection.

Performance Impact

The default configuration for this integration is not expected to impose a significant performance impact on the system.



No action required.



There is no configuration file.


There are no configuration options.


There are no configuration examples.


Metrics grouped by scope.

The scope defines the instance that the metric belongs to. An instance is uniquely identified by a set of labels.

Per ZFS Adaptive Replacement Cache instance

This scope has no labels.


Metric Dimensions Unit
zfs.arc_size arcsz, target, min, max MiB
zfs.l2_size actual, size MiB
zfs.reads arc, demand, prefetch, metadata, l2 reads/s
zfs.bytes read, write KiB/s
zfs.hits hits, misses percentage
zfs.hits_rate hits, misses events/s
zfs.dhits hits, misses percentage
zfs.dhits_rate hits, misses events/s
zfs.phits hits, misses percentage
zfs.phits_rate hits, misses events/s
zfs.mhits hits, misses percentage
zfs.mhits_rate hits, misses events/s
zfs.l2hits hits, misses percentage
zfs.l2hits_rate hits, misses events/s
zfs.list_hits mfu, mfu_ghost, mru, mru_ghost hits/s
zfs.arc_size_breakdown recent, frequent percentage
zfs.memory_ops direct, throttled, indirect operations/s
zfs.important_ops evict_skip, deleted, mutex_miss, hash_collisions operations/s
zfs.actual_hits hits, misses percentage
zfs.actual_hits_rate hits, misses events/s
zfs.demand_data_hits hits, misses percentage
zfs.demand_data_hits_rate hits, misses events/s
zfs.prefetch_data_hits hits, misses percentage
zfs.prefetch_data_hits_rate hits, misses events/s
zfs.hash_elements current, max elements
zfs.hash_chains current, max chains


The following alerts are available:

Alert name On metric Description
zfs_memory_throttle zfs.memory_ops number of times ZFS had to limit the ARC growth in the last 10 minutes

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