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.
arcstat [-havxp] [-f field[,field]...] [-o file] [-s string] [interval [count]]
The arcstat utility print various ZFS ARC and L2ARC statistics in vmstat-like fashion.
The arcstat command reports the following information:
c
ARC target size
Demand data hit percentage
Demand data miss percentage
MFU list hits per second
Metadata hit percentage
Metadata miss percentage
MRU list hits per second
Prefetch hits percentage
Prefetch miss percentage
Demand data hits per second
Demand data misses per second
ARC hit percentage
ARC reads per second
MFU ghost list hits per second
Metadata hits per second
ARC misses per second
Metadata misses per second
MRU ghost list hits per second
Prefetch hits per second
Prefetch misses per second
Total ARC accesses per second
Time
ARC size
Alias for size
Demand data accesses per second
evict_skip per second
ARC miss percentage
Metadata accesses per second
Prefetch accesses per second
L2ARC access hit percentage
L2ARC hits per second
L2ARC misses per second
Total L2ARC accesses per second
L2ARC prefetch allocated size per second
L2ARC prefetch allocated size percentage
L2ARC MFU allocated size per second
L2ARC MFU allocated size percentage
L2ARC MRU allocated size per second
L2ARC MRU allocated size percentage
L2ARC data (buf content) allocated size per second
L2ARC data (buf content) allocated size percentage
L2ARC metadata (buf content) allocated size per second
L2ARC metadata (buf content) allocated size percentage
Size of the L2ARC
mutex_miss per second
Bytes read per second from the L2ARC
L2ARC access miss percentage
Actual (compressed) size of the L2ARC
ARC grow disabled
ARC reclaim needed
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 avail above zero, avail is usually more instructive to observe than free.
The ARC's idea of how much free memory is available to it, which is a bit less than free. May temporarily be negative, in which case the ARC will reduce the target size c.
The following options are supported: -a
Print all possible stats.
Display only specific fields. See DESCRIPTION for supported statistics.
Display help message.
Report statistics to a file instead of the standard output.
Disable auto-scaling of numerical fields (for raw, machine-parsable values).
Display data with a specified separator (default: 2 spaces).
Print extended stats (same as -f time,mfu,mru,mfug,mrug,eskip,mtxmis,dread,pread,read).
Show field headers and definitions
The following operands are supported: count
Display only count reports.
Specify the sampling interval in seconds.
arcstat was originally written in Perl by Neelakanth Nadgir and supported only ZFS ARC statistics. Mike Harsch updated it to support L2ARC statistics. 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.