arcstat - report ZFS ARC and L2ARC statistics


ARCSTAT(1) General Commands Manual ARCSTAT(1)

NAME

arcstat — report ZFS ARC and L2ARC statistics

SYNOPSIS

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

DESCRIPTION

arcstat 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

l2miss%

L2ARC access miss percentage

l2asize

Actual (compressed) size of the L2ARC

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 December 23, 2022 ARCSTAT(1)


Updated 2024-01-29 - jenkler.se | uex.se