zarcstat - report ZFS ARC and L2ARC statistics

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ZARCSTAT(1) General Commands Manual ZARCSTAT(1)

NAME

zarcstat — report ZFS ARC and L2ARC statistics

SYNOPSIS

zarcstat [−havxp] [−f field[,fieldâ¦]] [−o file] [−s string] [interval] [count]

DESCRIPTION

zarcstat prints various ZFS ARC and L2ARC statistics in vmstat-like fashion:

c

ARC target size

dh%

Demand hit percentage

di%

Demand I/O hit percentage

dm%

Demand miss percentage

ddh%

Demand data hit percentage

ddi%

Demand data I/O hit percentage

ddm%

Demand data miss percentage

dmh%

Demand metadata hit percentage

dmi%

Demand metadata I/O hit percentage

dmm%

Demand metadata miss percentage

mfu

MFU list hits per second

mh%

Metadata hit percentage

mi%

Metadata I/O hit percentage

mm%

Metadata miss percentage

mru

MRU list hits per second

ph%

Prefetch hits percentage

pi%

Prefetch I/O hits percentage

pm%

Prefetch miss percentage

pdh%

Prefetch data hits percentage

pdi%

Prefetch data I/O hits percentage

pdm%

Prefetch data miss percentage

pmh%

Prefetch metadata hits percentage

pmi%

Prefetch metadata I/O hits percentage

pmm%

Prefetch metadata miss percentage

dhit

Demand hits per second

dioh

Demand I/O hits per second

dmis

Demand misses per second

ddhit

Demand data hits per second

ddioh

Demand data I/O hits per second

ddmis

Demand data misses per second

dmhit

Demand metadata hits per second

dmioh

Demand metadata I/O hits per second

dmmis

Demand metadata misses per second

hit%

ARC hit percentage

hits

ARC hits per second

ioh%

ARC I/O hits percentage

iohs

ARC I/O hits per second

mfug

MFU ghost list hits per second

mhit

Metadata hits per second

mioh

Metadata I/O hits per second

miss

ARC misses per second

mmis

Metadata misses per second

mrug

MRU ghost list hits per second

phit

Prefetch hits per second

pioh

Prefetch I/O hits per second

pmis

Prefetch misses per second

pdhit

Prefetch data hits per second

pdioh

Prefetch data I/O hits per second

pdmis

Prefetch data misses per second

pmhit

Prefetch metadata hits per second

pmioh

Prefetch metadata I/O hits per second

pmmis

Prefetch metadata misses per second

read

Total ARC accesses per second

time

Current time

size

ARC size

arcsz

Alias for size

unc

Uncached list hits per second

dread

Demand accesses per second

ddread

Demand data accesses per second

dmread

Demand metadata accesses per second

eskip

evict_skip per second

miss%

ARC miss percentage

mread

Metadata accesses per second

pread

Prefetch accesses per second

pdread

Prefetch data accesses per second

pmread

Prefetch metadata accesses per second

l2hit%

L2ARC access hit percentage

l2hits

L2ARC hits per second

l2miss

L2ARC misses per second

l2read

Total L2ARC accesses per second

l2pref

L2ARC prefetch allocated size per second

l2pref%

L2ARC prefetch allocated size percentage

l2mfu

L2ARC MFU allocated size per second

l2mfu%

L2ARC MFU allocated size percentage

l2mru

L2ARC MRU allocated size per second

l2mru%

L2ARC MRU allocated size percentage

l2data

L2ARC data (buf content) allocated size per second

l2data%

L2ARC data (buf content) allocated size percentage

l2meta

L2ARC metadata (buf content) allocated size per second

l2meta%

L2ARC metadata (buf content) allocated size percentage

l2size

Size of the L2ARC

mtxmis

mutex_miss per second

l2bytes

Bytes read per second from the L2ARC

l2wbytes

Bytes written per second to the L2ARC

l2miss%

L2ARC access miss percentage

l2asize

Actual (compressed) size of the L2ARC

cmpsz

Compressed size

cmpsz%

Compressed size percentage

ovhsz

Overhead size

ovhsz%

Overhead size percentage

bonsz

Bonus size

bonsz%

Bonus size percentage

dnosz

Dnode size

dnosz%

Dnode size percentage

dbusz

Dbuf size

dbusz%

Dbuf size percentage

hdrsz

Header size

hdrsz%

Header size percentage

l2hsz

L2 header size

l2hsz%

L2 header size percentage

abdsz

ABD chunk waste size

abdsz%

ABD chunk waste size percentage

datatg

ARC data target

datatg%

ARC data target percentage

datasz

ARC data size

datasz%

ARC data size percentage

metatg

ARC metadata target

metatg%

ARC metadata target percentage

metasz

ARC metadata size

metasz%

ARC metadata size percentage

anosz

Anonymous size

anosz%

Anonymous size percentage

anoda

Anonymous data size

anoda%

Anonymous data size percentage

anome

Anonymous metadata size

anome%

Anonymous metadata size percentage

anoed

Anonymous evictable data size

anoed%

Anonymous evictable data size percentage

anoem

Anonymous evictable metadata size

anoem%

Anonymous evictable metadata size percentage

mfutg

MFU target

mfutg%

MFU target percentage

mfudt

MFU data target

mfudt%

MFU data target percentage

mfumt

MFU metadata target

mfumt%

MFU metadata target percentage

mfusz

MFU size

mfusz%

MFU size percentage

mfuda

MFU data size

mfuda%

MFU data size percentage

mfume

MFU metadata size

mfume%

MFU metadata size percentage

mfued

MFU evictable data size

mfued%

MFU evictable data size percentage

mfuem

MFU evictable metadata size

mfuem%

MFU evictable metadata size percentage

mfugsz

MFU ghost size

mfugd

MFU ghost data size

mfugm

MFU ghost metadata size

mrutg

MRU target

mrutg%

MRU target percentage

mrudt

MRU data target

mrudt%

MRU data target percentage

mrumt

MRU metadata target

mrumt%

MRU metadata target percentage

mrusz

MRU size

mrusz%

MRU size percentage

mruda

MRU data size

mruda%

MRU data size percentage

mrume

MRU metadata size

mrume%

MRU metadata size percentage

mrued

MRU evictable data size

mrued%

MRU evictable data size percentage

mruem

MRU evictable metadata size

mruem%

MRU evictable metadata size percentage

mrugsz

MRU ghost size

mrugd

MRU ghost data size

mrugm

MRU ghost metadata size

uncsz

Uncached size

uncsz%

Uncached size percentage

uncda

Uncached data size

uncda%

Uncached data size percentage

uncme

Uncached metadata size

uncme%

Uncached metadata size percentage

unced

Uncached evictable data size

unced%

Uncached evictable data size percentage

uncem

Uncached evictable metadata size

uncem%

Uncached evictable metadata size percentage

grow

ARC grow disabled

need

ARC reclaim needed

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 avail above zero, avail is usually more instructive to observe than free.

avail

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.

OPTIONS
−a

Print all possible stats.

−f

Display only specific fields. See “DESCRIPTION” for supported statistics.

−h

Display help message.

−o

Report statistics to a file instead of the standard output.

−p

Disable auto-scaling of numerical fields (for raw, machine-parsable values).

−s

Display data with a specified separator (default: 2 spaces).

−x

Print extended stats (same as −f time,mfu,mru,mfug,mrug,eskip,mtxmis,dread,pread,read).

−v

Show field headers and definitions

OPERANDS

The following operands are supported:

interval

Specify the sampling interval in seconds.

count

Display only count reports. OpenZFS September 19, 2024 ZARCSTAT(1)

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