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.\" Common Development and Distribution License ("CDDL"), version 1.0.
.\" You may only use this file in accordance with the terms of version
.\" 1.0 of the CDDL.
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.\" Copyright 2014 Adam Stevko.  All rights reserved.
.\" Copyright (c) 2015 by Delphix. All rights reserved.
.\" Copyright (c) 2020 by AJ Jordan. All rights reserved.
.\"
.Dd December 23, 2022
.Dt ARCSTAT 1
.Os OpenZFS
.
.Sh NAME
.Nm arcstat
.Nd report ZFS ARC and L2ARC statistics
.Sh SYNOPSIS
.Nm
.Op Fl havxp
.Op Fl f Ar field Ns Op , Ns Ar field Ns …
.Op Fl o Ar file
.Op Fl s Ar string
.Op Ar interval
.Op Ar count
.
.Sh DESCRIPTION
.Nm
prints various ZFS ARC and L2ARC statistics in vmstat-like fashion:
.Bl -tag -compact -offset Ds -width "l2asize"
.It Sy c
ARC target size
.It Sy dh%
Demand hit percentage
.It Sy di%
Demand I/O hit percentage
.It Sy dm%
Demand miss percentage
.It Sy ddh%
Demand data hit percentage
.It Sy ddi%
Demand data I/O hit percentage
.It Sy ddm%
Demand data miss percentage
.It Sy dmh%
Demand metadata hit percentage
.It Sy dmi%
Demand metadata I/O hit percentage
.It Sy dmm%
Demand metadata miss percentage
.It Sy mfu
MFU list hits per second
.It Sy mh%
Metadata hit percentage
.It Sy mi%
Metadata I/O hit percentage
.It Sy mm%
Metadata miss percentage
.It Sy mru
MRU list hits per second
.It Sy ph%
Prefetch hits percentage
.It Sy pi%
Prefetch I/O hits percentage
.It Sy pm%
Prefetch miss percentage
.It Sy pdh%
Prefetch data hits percentage
.It Sy pdi%
Prefetch data I/O hits percentage
.It Sy pdm%
Prefetch data miss percentage
.It Sy pmh%
Prefetch metadata hits percentage
.It Sy pmi%
Prefetch metadata I/O hits percentage
.It Sy pmm%
Prefetch metadata miss percentage
.It Sy dhit
Demand hits per second
.It Sy dioh
Demand I/O hits per second
.It Sy dmis
Demand misses per second
.It Sy ddhit
Demand data hits per second
.It Sy ddioh
Demand data I/O hits per second
.It Sy ddmis
Demand data misses per second
.It Sy dmhit
Demand metadata hits per second
.It Sy dmioh
Demand metadata I/O hits per second
.It Sy dmmis
Demand metadata misses per second
.It Sy hit%
ARC hit percentage
.It Sy hits
ARC hits per second
.It Sy ioh%
ARC I/O hits percentage
.It Sy iohs
ARC I/O hits per second
.It Sy mfug
MFU ghost list hits per second
.It Sy mhit
Metadata hits per second
.It Sy mioh
Metadata I/O hits per second
.It Sy miss
ARC misses per second
.It Sy mmis
Metadata misses per second
.It Sy mrug
MRU ghost list hits per second
.It Sy phit
Prefetch hits per second
.It Sy pioh
Prefetch I/O hits per second
.It Sy pmis
Prefetch misses per second
.It Sy pdhit
Prefetch data hits per second
.It Sy pdioh
Prefetch data I/O hits per second
.It Sy pdmis
Prefetch data misses per second
.It Sy pmhit
Prefetch metadata hits per second
.It Sy pmioh
Prefetch metadata I/O hits per second
.It Sy pmmis
Prefetch metadata misses per second
.It Sy read
Total ARC accesses per second
.It Sy time
Current time
.It Sy size
ARC size
.It Sy arcsz
Alias for
.Sy size
.It Sy unc
Uncached list hits per second
.It Sy dread
Demand accesses per second
.It Sy ddread
Demand data accesses per second
.It Sy dmread
Demand metadata accesses per second
.It Sy eskip
evict_skip per second
.It Sy miss%
ARC miss percentage
.It Sy mread
Metadata accesses per second
.It Sy pread
Prefetch accesses per second
.It Sy pdread
Prefetch data accesses per second
.It Sy pmread
Prefetch metadata accesses per second
.It Sy l2hit%
L2ARC access hit percentage
.It Sy l2hits
L2ARC hits per second
.It Sy l2miss
L2ARC misses per second
.It Sy l2read
Total L2ARC accesses per second
.It Sy l2pref
L2ARC prefetch allocated size per second
.It Sy l2pref%
L2ARC prefetch allocated size percentage
.It Sy l2mfu
L2ARC MFU allocated size per second
.It Sy l2mfu%
L2ARC MFU allocated size percentage
.It Sy l2mru
L2ARC MRU allocated size per second
.It Sy l2mru%
L2ARC MRU allocated size percentage
.It Sy l2data
L2ARC data (buf content) allocated size per second
.It Sy l2data%
L2ARC data (buf content) allocated size percentage
.It Sy l2meta
L2ARC metadata (buf content) allocated size per second
.It Sy l2meta%
L2ARC metadata (buf content) allocated size percentage
.It Sy l2size
Size of the L2ARC
.It Sy mtxmis
mutex_miss per second
.It Sy l2bytes
Bytes read per second from the L2ARC
.It Sy l2miss%
L2ARC access miss percentage
.It Sy l2asize
Actual (compressed) size of the L2ARC
.It Sy grow
ARC grow disabled
.It Sy need
ARC reclaim needed
.It Sy free
The ARC's idea of how much free memory there is, which includes evictable memory
in the page cache.
Since the ARC tries to keep
.Sy avail
above zero,
.Sy avail
is usually more instructive to observe than
.Sy free .
.It Sy avail
The ARC's idea of how much free memory is available to it, which is a bit less
than
.Sy free .
May temporarily be negative, in which case the ARC will reduce the target size
.Sy c .
.El
.
.Sh OPTIONS
.Bl -tag -width "-v"
.It Fl a
Print all possible stats.
.It Fl f
Display only specific fields.
See
.Sx DESCRIPTION
for supported statistics.
.It Fl h
Display help message.
.It Fl o
Report statistics to a file instead of the standard output.
.It Fl p
Disable auto-scaling of numerical fields (for raw, machine-parsable values).
.It Fl s
Display data with a specified separator (default: 2 spaces).
.It Fl x
Print extended stats
.Pq same as Fl f Sy time , Ns Sy mfu , Ns Sy mru , Ns Sy mfug , Ns Sy mrug , Ns Sy eskip , Ns Sy mtxmis , Ns Sy dread , Ns Sy pread , Ns Sy read .
.It Fl v
Show field headers and definitions
.El
.
.Sh OPERANDS
The following operands are supported:
.Bl -tag -compact -offset Ds -width "interval"
.It Ar interval
Specify the sampling interval in seconds.
.It Ar count
Display only
.Ar count
reports.
.El