.\"
.\" This file and its contents are supplied under the terms of the
.\" 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.
.\"
.\" A full copy of the text of the CDDL should have accompanied this
.\" source.  A copy of the CDDL is also available via the Internet at
.\" http://www.illumos.org/license/CDDL.
.\"
.\" 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 May 26, 2021
.Dt ARCSTAT 1
.Os
.
.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 -width "l2asize"
.It Sy c
ARC target size
.It Sy dh%
Demand data hit percentage
.It Sy dm%
Demand data miss percentage
.It Sy mfu
MFU list hits per second
.It Sy mh%
Metadata hit percentage
.It Sy mm%
Metadata miss percentage
.It Sy mru
MRU list hits per second
.It Sy ph%
Prefetch hits percentage
.It Sy pm%
Prefetch miss percentage
.It Sy dhit
Demand data hits per second
.It Sy dmis
Demand data misses per second
.It Sy hit%
ARC hit percentage
.It Sy hits
ARC reads per second
.It Sy mfug
MFU ghost list hits per second
.It Sy mhit
Metadata 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 pmis
Prefetch 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 dread
Demand data 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 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
.Sy 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 (same as
.Fl f Ar time,mfu,mru,mfug,mrug,eskip,mtxmis,dread,pread,read Ns No ).
.It Fl v
Show field headers and definitions
.El
.
.Sh OPERANDS
The following operands are supported:
.Bl -tag -width "interval"
.It Ar interval
Specify the sampling interval in seconds.
.It Ar count
Display only \fIcount\fR reports.
.El