arcstat - report ZFS ARC and L2ARC statistics
arcstat [-hvxr] [-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
dh% 
Demand Data hit percentage
dm% 
Demand Data miss percentage
mfu 
MFU List hits per second
mh% 
Metadata hit percentage
mm% 
Metadata miss percentage
mru 
MRU List hits per second
ph% 
Prefetch hits percentage
pm% 
Prefetch miss percentage
dhit 
Demand Data hits per second
dmis 
Demand Data misses per second
hit% 
ARC Hit percentage
hits 
ARC reads per second
mfug 
MFU Ghost List hits per second
mhit 
Metadata 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
pmis 
Prefetch misses per second
read 
Total ARC accesses per second
time 
Time
arcsz 
ARC Size
dread 
Demand data accesses per second
eskip 
evict_skip per second
miss% 
ARC miss percentage
mread 
Metadata accesses per second
pread 
Prefetch 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
The following options are supported:
-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.
-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
The following operands are supported:
count
Display only count reports.
interval
Specify the sampling interval in seconds.
arcstat was originally written by Neelakanth Nadgir and supported
    only ZFS ARC statistics. Mike Harsch updated it to support L2ARC
  statistics.