2 .\" This file and its contents are supplied under the terms of the
3 .\" Common Development and Distribution License ("CDDL"), version 1.0.
4 .\" You may only use this file in accordance with the terms of version
7 .\" A full copy of the text of the CDDL should have accompanied this
8 .\" source. A copy of the CDDL is also available via the Internet at
9 .\" http://www.illumos.org/license/CDDL.
12 .\" Copyright 2014 Adam Stevko. All rights reserved.
13 .\" Copyright (c) 2015 by Delphix. All rights reserved.
14 .\" Copyright (c) 2020 by AJ Jordan. All rights reserved.
16 .TH ARCSTAT 1 "Aug 24, 2020" OpenZFS
18 arcstat \- report ZFS ARC and L2ARC statistics
22 \fBarcstat\fR [\fB-hvx\fR] [\fB-f field[,field]...\fR] [\fB-o file\fR] [\fB-s string\fR] [\fBinterval\fR [\fBcount\fR]]
27 The \fBarcstat\fR utility print various ZFS ARC and L2ARC statistics in
33 The \fBarcstat\fR command reports the following information:
53 Demand data hit percentage
62 Demand data miss percentage
71 MFU list hits per second
80 Metadata hit percentage
89 Metadata miss percentage
98 MRU list hits per second
107 Prefetch hits percentage
116 Prefetch miss percentage
125 Demand data hits per second
134 Demand data misses per second
161 MFU ghost list hits per second
170 Metadata hits per second
179 ARC misses per second
188 Metadata misses per second
197 MRU ghost list hits per second
206 Prefetch hits per second
215 Prefetch misses per second
224 Total ARC accesses per second
260 Demand data accesses per second
269 evict_skip per second
287 Metadata accesses per second
296 Prefetch accesses per second
305 L2ARC access hit percentage
314 L2ARC hits per second
323 L2ARC misses per second
332 Total L2ARC accesses per second
350 mutex_miss per second
359 Bytes read per second from the L2ARC
368 L2ARC access miss percentage
377 Actual (compressed) size of the L2ARC
404 The ARC's idea of how much free memory there is, which includes evictable memory in the page cache.
405 Since the ARC tries to keep \fBavail\fR above zero, \fBavail\fR is usually more instructive to observe than \fBfree\fR.
414 The ARC's idea of how much free memory is available to it, which is a bit less than \fBfree\fR.
415 May temporarily be negative, in which case the ARC will reduce the target size \fBc\fR.
421 The following options are supported:
429 Display only specific fields. See \fBDESCRIPTION\fR for supported statistics.
438 Display help message.
447 Report statistics to a file instead of the standard output.
456 Display data with a specified separator (default: 2 spaces).
465 Print extended stats (same as -f time,mfu,mru,mfug,mrug,eskip,mtxmis,dread,pread,read).
474 Show field headers and definitions
479 The following operands are supported:
486 Display only \fIcount\fR reports.
495 Specify the sampling interval in seconds.
500 arcstat was originally written in Perl by Neelakanth Nadgir and supported only ZFS ARC statistics.
501 Mike Harsch updated it to support L2ARC statistics.
502 John Hixson ported it to Python for FreeNAS over some beer, after which many individuals from the OpenZFS community continued to maintain and improve it.