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mirror_zfs/cmd/arc_summary/arc_summary2
George Amanakis 085321621e
Add L2ARC arcstats for MFU/MRU buffers and buffer content type 
Currently the ARC state (MFU/MRU) of cached L2ARC buffer and their
content type is unknown. Knowing this information may prove beneficial
in adjusting the L2ARC caching policy.

This commit adds L2ARC arcstats that display the aligned size
(in bytes) of L2ARC buffers according to their content type
(data/metadata) and according to their ARC state (MRU/MFU or
prefetch). It also expands the existing evict_l2_eligible arcstat to
differentiate between MFU and MRU buffers.

L2ARC caches buffers from the MRU and MFU lists of ARC. Upon caching a
buffer, its ARC state (MRU/MFU) is stored in the L2 header
(b_arcs_state). The l2_m{f,r}u_asize arcstats reflect the aligned size
(in bytes) of L2ARC buffers according to their ARC state (based on
b_arcs_state). We also account for the case where an L2ARC and ARC
cached MRU or MRU_ghost buffer transitions to MFU. The l2_prefetch_asize
reflects the alinged size (in bytes) of L2ARC buffers that were cached
while they had the prefetch flag set in ARC. This is dynamically updated
as the prefetch flag of L2ARC buffers changes.

When buffers are evicted from ARC, if they are determined to be L2ARC
eligible then their logical size is recorded in
evict_l2_eligible_m{r,f}u arcstats according to their ARC state upon
eviction.

Persistent L2ARC:
When committing an L2ARC buffer to a log block (L2ARC metadata) its
b_arcs_state and prefetch flag is also stored. If the buffer changes
its arcstate or prefetch flag this is reflected in the above arcstats.
However, the L2ARC metadata cannot currently be updated to reflect this
change.
Example: L2ARC caches an MRU buffer. L2ARC metadata and arcstats count
this as an MRU buffer. The buffer transitions to MFU. The arcstats are
updated to reflect this. Upon pool re-import or on/offlining the L2ARC
device the arcstats are cleared and the buffer will now be counted as an
MRU buffer, as the L2ARC metadata were not updated.

Bug fix:
- If l2arc_noprefetch is set, arc_read_done clears the L2CACHE flag of
  an ARC buffer. However, prefetches may be issued in a way that
  arc_read_done() is bypassed. Instead, move the related code in
  l2arc_write_eligible() to account for those cases too.

Also add a test and update manpages for l2arc_mfuonly module parameter,
and update the manpages and code comments for l2arc_noprefetch.
Move persist_l2arc tests to l2arc.

Reviewed-by: Ryan Moeller <freqlabs@FreeBSD.org>
Reviewed-by: Richard Elling <Richard.Elling@RichardElling.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: George Amanakis <gamanakis@gmail.com>
Closes #10743
2020-09-14 10:10:44 -07:00

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#!/usr/bin/env python2
#
# $Id: arc_summary.pl,v 388:e27800740aa2 2011-07-08 02:53:29Z jhell $
#
# Copyright (c) 2008 Ben Rockwood <benr@cuddletech.com>,
# Copyright (c) 2010 Martin Matuska <mm@FreeBSD.org>,
# Copyright (c) 2010-2011 Jason J. Hellenthal <jhell@DataIX.net>,
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
#
# 1. Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
# SUCH DAMAGE.
#
# If you are having troubles when using this script from cron(8) please try
# adjusting your PATH before reporting problems.
#
# Note some of this code uses older code (eg getopt instead of argparse,
# subprocess.Popen() instead of subprocess.run()) because we need to support
# some very old versions of Python.
#
"""Print statistics on the ZFS Adjustable Replacement Cache (ARC)
Provides basic information on the ARC, its efficiency, the L2ARC (if present),
the Data Management Unit (DMU), Virtual Devices (VDEVs), and tunables. See the
in-source documentation and code at
https://github.com/zfsonlinux/zfs/blob/master/module/zfs/arc.c for details.
"""
import getopt
import os
import sys
import time
import errno
from subprocess import Popen, PIPE
from decimal import Decimal as D
if sys.platform.startswith('freebsd'):
# Requires py27-sysctl on FreeBSD
import sysctl
def load_kstats(namespace):
"""Collect information on a specific subsystem of the ARC"""
base = 'kstat.zfs.misc.%s.' % namespace
return [(kstat.name, D(kstat.value)) for kstat in sysctl.filter(base)]
def load_tunables():
return dict((ctl.name, ctl.value) for ctl in sysctl.filter('vfs.zfs'))
elif sys.platform.startswith('linux'):
def load_kstats(namespace):
"""Collect information on a specific subsystem of the ARC"""
kstat = 'kstat.zfs.misc.%s.%%s' % namespace
path = '/proc/spl/kstat/zfs/%s' % namespace
with open(path) as f:
entries = [line.strip().split() for line in f][2:] # Skip header
return [(kstat % name, D(value)) for name, _, value in entries]
def load_tunables():
basepath = '/sys/module/zfs/parameters'
tunables = {}
for name in os.listdir(basepath):
if not name:
continue
path = '%s/%s' % (basepath, name)
with open(path) as f:
value = f.read()
tunables[name] = value.strip()
return tunables
show_tunable_descriptions = False
alternate_tunable_layout = False
def handle_Exception(ex_cls, ex, tb):
if ex is IOError:
if ex.errno == errno.EPIPE:
sys.exit()
if ex is KeyboardInterrupt:
sys.exit()
sys.excepthook = handle_Exception
def get_Kstat():
"""Collect information on the ZFS subsystem from the /proc virtual
file system. The name "kstat" is a holdover from the Solaris utility
of the same name.
"""
Kstat = {}
Kstat.update(load_kstats('arcstats'))
Kstat.update(load_kstats('zfetchstats'))
Kstat.update(load_kstats('vdev_cache_stats'))
return Kstat
def fBytes(b=0):
"""Return human-readable representation of a byte value in
powers of 2 (eg "KiB" for "kibibytes", etc) to two decimal
points. Values smaller than one KiB are returned without
decimal points.
"""
prefixes = [
[2**80, "YiB"], # yobibytes (yotta)
[2**70, "ZiB"], # zebibytes (zetta)
[2**60, "EiB"], # exbibytes (exa)
[2**50, "PiB"], # pebibytes (peta)
[2**40, "TiB"], # tebibytes (tera)
[2**30, "GiB"], # gibibytes (giga)
[2**20, "MiB"], # mebibytes (mega)
[2**10, "KiB"]] # kibibytes (kilo)
if b >= 2**10:
for limit, unit in prefixes:
if b >= limit:
value = b / limit
break
result = "%0.2f\t%s" % (value, unit)
else:
result = "%d\tBytes" % b
return result
def fHits(hits=0):
"""Create a human-readable representation of the number of hits.
The single-letter symbols used are SI to avoid the confusion caused
by the different "short scale" and "long scale" representations in
English, which use the same words for different values. See
https://en.wikipedia.org/wiki/Names_of_large_numbers and
https://physics.nist.gov/cuu/Units/prefixes.html
"""
numbers = [
[10**24, 'Y'], # yotta (septillion)
[10**21, 'Z'], # zetta (sextillion)
[10**18, 'E'], # exa (quintrillion)
[10**15, 'P'], # peta (quadrillion)
[10**12, 'T'], # tera (trillion)
[10**9, 'G'], # giga (billion)
[10**6, 'M'], # mega (million)
[10**3, 'k']] # kilo (thousand)
if hits >= 1000:
for limit, symbol in numbers:
if hits >= limit:
value = hits/limit
break
result = "%0.2f%s" % (value, symbol)
else:
result = "%d" % hits
return result
def fPerc(lVal=0, rVal=0, Decimal=2):
"""Calculate percentage value and return in human-readable format"""
if rVal > 0:
return str("%0." + str(Decimal) + "f") % (100 * (lVal / rVal)) + "%"
else:
return str("%0." + str(Decimal) + "f") % 100 + "%"
def get_arc_summary(Kstat):
"""Collect general data on the ARC"""
output = {}
memory_throttle_count = Kstat[
"kstat.zfs.misc.arcstats.memory_throttle_count"
]
if memory_throttle_count > 0:
output['health'] = 'THROTTLED'
else:
output['health'] = 'HEALTHY'
output['memory_throttle_count'] = fHits(memory_throttle_count)
# ARC Misc.
deleted = Kstat["kstat.zfs.misc.arcstats.deleted"]
mutex_miss = Kstat["kstat.zfs.misc.arcstats.mutex_miss"]
evict_skip = Kstat["kstat.zfs.misc.arcstats.evict_skip"]
evict_l2_cached = Kstat["kstat.zfs.misc.arcstats.evict_l2_cached"]
evict_l2_eligible = Kstat["kstat.zfs.misc.arcstats.evict_l2_eligible"]
evict_l2_eligible_mfu = Kstat["kstat.zfs.misc.arcstats.evict_l2_eligible_mfu"]
evict_l2_eligible_mru = Kstat["kstat.zfs.misc.arcstats.evict_l2_eligible_mru"]
evict_l2_ineligible = Kstat["kstat.zfs.misc.arcstats.evict_l2_ineligible"]
evict_l2_skip = Kstat["kstat.zfs.misc.arcstats.evict_l2_skip"]
# ARC Misc.
output["arc_misc"] = {}
output["arc_misc"]["deleted"] = fHits(deleted)
output["arc_misc"]["mutex_miss"] = fHits(mutex_miss)
output["arc_misc"]["evict_skips"] = fHits(evict_skip)
output["arc_misc"]["evict_l2_skip"] = fHits(evict_l2_skip)
output["arc_misc"]["evict_l2_cached"] = fBytes(evict_l2_cached)
output["arc_misc"]["evict_l2_eligible"] = fBytes(evict_l2_eligible)
output["arc_misc"]["evict_l2_eligible_mfu"] = {
'per': fPerc(evict_l2_eligible_mfu, evict_l2_eligible),
'num': fBytes(evict_l2_eligible_mfu),
}
output["arc_misc"]["evict_l2_eligible_mru"] = {
'per': fPerc(evict_l2_eligible_mru, evict_l2_eligible),
'num': fBytes(evict_l2_eligible_mru),
}
output["arc_misc"]["evict_l2_ineligible"] = fBytes(evict_l2_ineligible)
# ARC Sizing
arc_size = Kstat["kstat.zfs.misc.arcstats.size"]
mru_size = Kstat["kstat.zfs.misc.arcstats.mru_size"]
mfu_size = Kstat["kstat.zfs.misc.arcstats.mfu_size"]
meta_limit = Kstat["kstat.zfs.misc.arcstats.arc_meta_limit"]
meta_size = Kstat["kstat.zfs.misc.arcstats.arc_meta_used"]
dnode_limit = Kstat["kstat.zfs.misc.arcstats.arc_dnode_limit"]
dnode_size = Kstat["kstat.zfs.misc.arcstats.dnode_size"]
target_max_size = Kstat["kstat.zfs.misc.arcstats.c_max"]
target_min_size = Kstat["kstat.zfs.misc.arcstats.c_min"]
target_size = Kstat["kstat.zfs.misc.arcstats.c"]
target_size_ratio = (target_max_size / target_min_size)
# ARC Sizing
output['arc_sizing'] = {}
output['arc_sizing']['arc_size'] = {
'per': fPerc(arc_size, target_max_size),
'num': fBytes(arc_size),
}
output['arc_sizing']['target_max_size'] = {
'ratio': target_size_ratio,
'num': fBytes(target_max_size),
}
output['arc_sizing']['target_min_size'] = {
'per': fPerc(target_min_size, target_max_size),
'num': fBytes(target_min_size),
}
output['arc_sizing']['target_size'] = {
'per': fPerc(target_size, target_max_size),
'num': fBytes(target_size),
}
output['arc_sizing']['meta_limit'] = {
'per': fPerc(meta_limit, target_max_size),
'num': fBytes(meta_limit),
}
output['arc_sizing']['meta_size'] = {
'per': fPerc(meta_size, meta_limit),
'num': fBytes(meta_size),
}
output['arc_sizing']['dnode_limit'] = {
'per': fPerc(dnode_limit, meta_limit),
'num': fBytes(dnode_limit),
}
output['arc_sizing']['dnode_size'] = {
'per': fPerc(dnode_size, dnode_limit),
'num': fBytes(dnode_size),
}
# ARC Hash Breakdown
output['arc_hash_break'] = {}
output['arc_hash_break']['hash_chain_max'] = Kstat[
"kstat.zfs.misc.arcstats.hash_chain_max"
]
output['arc_hash_break']['hash_chains'] = Kstat[
"kstat.zfs.misc.arcstats.hash_chains"
]
output['arc_hash_break']['hash_collisions'] = Kstat[
"kstat.zfs.misc.arcstats.hash_collisions"
]
output['arc_hash_break']['hash_elements'] = Kstat[
"kstat.zfs.misc.arcstats.hash_elements"
]
output['arc_hash_break']['hash_elements_max'] = Kstat[
"kstat.zfs.misc.arcstats.hash_elements_max"
]
output['arc_size_break'] = {}
output['arc_size_break']['recently_used_cache_size'] = {
'per': fPerc(mru_size, mru_size + mfu_size),
'num': fBytes(mru_size),
}
output['arc_size_break']['frequently_used_cache_size'] = {
'per': fPerc(mfu_size, mru_size + mfu_size),
'num': fBytes(mfu_size),
}
# ARC Hash Breakdown
hash_chain_max = Kstat["kstat.zfs.misc.arcstats.hash_chain_max"]
hash_chains = Kstat["kstat.zfs.misc.arcstats.hash_chains"]
hash_collisions = Kstat["kstat.zfs.misc.arcstats.hash_collisions"]
hash_elements = Kstat["kstat.zfs.misc.arcstats.hash_elements"]
hash_elements_max = Kstat["kstat.zfs.misc.arcstats.hash_elements_max"]
output['arc_hash_break'] = {}
output['arc_hash_break']['elements_max'] = fHits(hash_elements_max)
output['arc_hash_break']['elements_current'] = {
'per': fPerc(hash_elements, hash_elements_max),
'num': fHits(hash_elements),
}
output['arc_hash_break']['collisions'] = fHits(hash_collisions)
output['arc_hash_break']['chain_max'] = fHits(hash_chain_max)
output['arc_hash_break']['chains'] = fHits(hash_chains)
return output
def _arc_summary(Kstat):
"""Print information on the ARC"""
# ARC Sizing
arc = get_arc_summary(Kstat)
sys.stdout.write("ARC Summary: (%s)\n" % arc['health'])
sys.stdout.write("\tMemory Throttle Count:\t\t\t%s\n" %
arc['memory_throttle_count'])
sys.stdout.write("\n")
# ARC Misc.
sys.stdout.write("ARC Misc:\n")
sys.stdout.write("\tDeleted:\t\t\t\t%s\n" % arc['arc_misc']['deleted'])
sys.stdout.write("\tMutex Misses:\t\t\t\t%s\n" %
arc['arc_misc']['mutex_miss'])
sys.stdout.write("\tEviction Skips:\t\t\t\t%s\n" %
arc['arc_misc']['evict_skips'])
sys.stdout.write("\tEviction Skips Due to L2 Writes:\t%s\n" %
arc['arc_misc']['evict_l2_skip'])
sys.stdout.write("\tL2 Cached Evictions:\t\t\t%s\n" %
arc['arc_misc']['evict_l2_cached'])
sys.stdout.write("\tL2 Eligible Evictions:\t\t\t%s\n" %
arc['arc_misc']['evict_l2_eligible'])
sys.stdout.write("\tL2 Eligible MFU Evictions:\t%s\t%s\n" % (
arc['arc_misc']['evict_l2_eligible_mfu']['per'],
arc['arc_misc']['evict_l2_eligible_mfu']['num'],
)
)
sys.stdout.write("\tL2 Eligible MRU Evictions:\t%s\t%s\n" % (
arc['arc_misc']['evict_l2_eligible_mru']['per'],
arc['arc_misc']['evict_l2_eligible_mru']['num'],
)
)
sys.stdout.write("\tL2 Ineligible Evictions:\t\t%s\n" %
arc['arc_misc']['evict_l2_ineligible'])
sys.stdout.write("\n")
# ARC Sizing
sys.stdout.write("ARC Size:\t\t\t\t%s\t%s\n" % (
arc['arc_sizing']['arc_size']['per'],
arc['arc_sizing']['arc_size']['num']
)
)
sys.stdout.write("\tTarget Size: (Adaptive)\t\t%s\t%s\n" % (
arc['arc_sizing']['target_size']['per'],
arc['arc_sizing']['target_size']['num'],
)
)
sys.stdout.write("\tMin Size (Hard Limit):\t\t%s\t%s\n" % (
arc['arc_sizing']['target_min_size']['per'],
arc['arc_sizing']['target_min_size']['num'],
)
)
sys.stdout.write("\tMax Size (High Water):\t\t%d:1\t%s\n" % (
arc['arc_sizing']['target_max_size']['ratio'],
arc['arc_sizing']['target_max_size']['num'],
)
)
sys.stdout.write("\nARC Size Breakdown:\n")
sys.stdout.write("\tRecently Used Cache Size:\t%s\t%s\n" % (
arc['arc_size_break']['recently_used_cache_size']['per'],
arc['arc_size_break']['recently_used_cache_size']['num'],
)
)
sys.stdout.write("\tFrequently Used Cache Size:\t%s\t%s\n" % (
arc['arc_size_break']['frequently_used_cache_size']['per'],
arc['arc_size_break']['frequently_used_cache_size']['num'],
)
)
sys.stdout.write("\tMetadata Size (Hard Limit):\t%s\t%s\n" % (
arc['arc_sizing']['meta_limit']['per'],
arc['arc_sizing']['meta_limit']['num'],
)
)
sys.stdout.write("\tMetadata Size:\t\t\t%s\t%s\n" % (
arc['arc_sizing']['meta_size']['per'],
arc['arc_sizing']['meta_size']['num'],
)
)
sys.stdout.write("\tDnode Size (Hard Limit):\t%s\t%s\n" % (
arc['arc_sizing']['dnode_limit']['per'],
arc['arc_sizing']['dnode_limit']['num'],
)
)
sys.stdout.write("\tDnode Size:\t\t\t%s\t%s\n" % (
arc['arc_sizing']['dnode_size']['per'],
arc['arc_sizing']['dnode_size']['num'],
)
)
sys.stdout.write("\n")
# ARC Hash Breakdown
sys.stdout.write("ARC Hash Breakdown:\n")
sys.stdout.write("\tElements Max:\t\t\t\t%s\n" %
arc['arc_hash_break']['elements_max'])
sys.stdout.write("\tElements Current:\t\t%s\t%s\n" % (
arc['arc_hash_break']['elements_current']['per'],
arc['arc_hash_break']['elements_current']['num'],
)
)
sys.stdout.write("\tCollisions:\t\t\t\t%s\n" %
arc['arc_hash_break']['collisions'])
sys.stdout.write("\tChain Max:\t\t\t\t%s\n" %
arc['arc_hash_break']['chain_max'])
sys.stdout.write("\tChains:\t\t\t\t\t%s\n" %
arc['arc_hash_break']['chains'])
def get_arc_efficiency(Kstat):
"""Collect information on the efficiency of the ARC"""
output = {}
arc_hits = Kstat["kstat.zfs.misc.arcstats.hits"]
arc_misses = Kstat["kstat.zfs.misc.arcstats.misses"]
demand_data_hits = Kstat["kstat.zfs.misc.arcstats.demand_data_hits"]
demand_data_misses = Kstat["kstat.zfs.misc.arcstats.demand_data_misses"]
demand_metadata_hits = Kstat[
"kstat.zfs.misc.arcstats.demand_metadata_hits"
]
demand_metadata_misses = Kstat[
"kstat.zfs.misc.arcstats.demand_metadata_misses"
]
mfu_ghost_hits = Kstat["kstat.zfs.misc.arcstats.mfu_ghost_hits"]
mfu_hits = Kstat["kstat.zfs.misc.arcstats.mfu_hits"]
mru_ghost_hits = Kstat["kstat.zfs.misc.arcstats.mru_ghost_hits"]
mru_hits = Kstat["kstat.zfs.misc.arcstats.mru_hits"]
prefetch_data_hits = Kstat["kstat.zfs.misc.arcstats.prefetch_data_hits"]
prefetch_data_misses = Kstat[
"kstat.zfs.misc.arcstats.prefetch_data_misses"
]
prefetch_metadata_hits = Kstat[
"kstat.zfs.misc.arcstats.prefetch_metadata_hits"
]
prefetch_metadata_misses = Kstat[
"kstat.zfs.misc.arcstats.prefetch_metadata_misses"
]
anon_hits = arc_hits - (
mfu_hits + mru_hits + mfu_ghost_hits + mru_ghost_hits
)
arc_accesses_total = (arc_hits + arc_misses)
demand_data_total = (demand_data_hits + demand_data_misses)
prefetch_data_total = (prefetch_data_hits + prefetch_data_misses)
real_hits = (mfu_hits + mru_hits)
output["total_accesses"] = fHits(arc_accesses_total)
output["cache_hit_ratio"] = {
'per': fPerc(arc_hits, arc_accesses_total),
'num': fHits(arc_hits),
}
output["cache_miss_ratio"] = {
'per': fPerc(arc_misses, arc_accesses_total),
'num': fHits(arc_misses),
}
output["actual_hit_ratio"] = {
'per': fPerc(real_hits, arc_accesses_total),
'num': fHits(real_hits),
}
output["data_demand_efficiency"] = {
'per': fPerc(demand_data_hits, demand_data_total),
'num': fHits(demand_data_total),
}
if prefetch_data_total > 0:
output["data_prefetch_efficiency"] = {
'per': fPerc(prefetch_data_hits, prefetch_data_total),
'num': fHits(prefetch_data_total),
}
if anon_hits > 0:
output["cache_hits_by_cache_list"] = {}
output["cache_hits_by_cache_list"]["anonymously_used"] = {
'per': fPerc(anon_hits, arc_hits),
'num': fHits(anon_hits),
}
output["most_recently_used"] = {
'per': fPerc(mru_hits, arc_hits),
'num': fHits(mru_hits),
}
output["most_frequently_used"] = {
'per': fPerc(mfu_hits, arc_hits),
'num': fHits(mfu_hits),
}
output["most_recently_used_ghost"] = {
'per': fPerc(mru_ghost_hits, arc_hits),
'num': fHits(mru_ghost_hits),
}
output["most_frequently_used_ghost"] = {
'per': fPerc(mfu_ghost_hits, arc_hits),
'num': fHits(mfu_ghost_hits),
}
output["cache_hits_by_data_type"] = {}
output["cache_hits_by_data_type"]["demand_data"] = {
'per': fPerc(demand_data_hits, arc_hits),
'num': fHits(demand_data_hits),
}
output["cache_hits_by_data_type"]["prefetch_data"] = {
'per': fPerc(prefetch_data_hits, arc_hits),
'num': fHits(prefetch_data_hits),
}
output["cache_hits_by_data_type"]["demand_metadata"] = {
'per': fPerc(demand_metadata_hits, arc_hits),
'num': fHits(demand_metadata_hits),
}
output["cache_hits_by_data_type"]["prefetch_metadata"] = {
'per': fPerc(prefetch_metadata_hits, arc_hits),
'num': fHits(prefetch_metadata_hits),
}
output["cache_misses_by_data_type"] = {}
output["cache_misses_by_data_type"]["demand_data"] = {
'per': fPerc(demand_data_misses, arc_misses),
'num': fHits(demand_data_misses),
}
output["cache_misses_by_data_type"]["prefetch_data"] = {
'per': fPerc(prefetch_data_misses, arc_misses),
'num': fHits(prefetch_data_misses),
}
output["cache_misses_by_data_type"]["demand_metadata"] = {
'per': fPerc(demand_metadata_misses, arc_misses),
'num': fHits(demand_metadata_misses),
}
output["cache_misses_by_data_type"]["prefetch_metadata"] = {
'per': fPerc(prefetch_metadata_misses, arc_misses),
'num': fHits(prefetch_metadata_misses),
}
return output
def _arc_efficiency(Kstat):
"""Print information on the efficiency of the ARC"""
arc = get_arc_efficiency(Kstat)
sys.stdout.write("ARC Total accesses:\t\t\t\t\t%s\n" %
arc['total_accesses'])
sys.stdout.write("\tCache Hit Ratio:\t\t%s\t%s\n" % (
arc['cache_hit_ratio']['per'],
arc['cache_hit_ratio']['num'],
)
)
sys.stdout.write("\tCache Miss Ratio:\t\t%s\t%s\n" % (
arc['cache_miss_ratio']['per'],
arc['cache_miss_ratio']['num'],
)
)
sys.stdout.write("\tActual Hit Ratio:\t\t%s\t%s\n" % (
arc['actual_hit_ratio']['per'],
arc['actual_hit_ratio']['num'],
)
)
sys.stdout.write("\n")
sys.stdout.write("\tData Demand Efficiency:\t\t%s\t%s\n" % (
arc['data_demand_efficiency']['per'],
arc['data_demand_efficiency']['num'],
)
)
if 'data_prefetch_efficiency' in arc:
sys.stdout.write("\tData Prefetch Efficiency:\t%s\t%s\n" % (
arc['data_prefetch_efficiency']['per'],
arc['data_prefetch_efficiency']['num'],
)
)
sys.stdout.write("\n")
sys.stdout.write("\tCACHE HITS BY CACHE LIST:\n")
if 'cache_hits_by_cache_list' in arc:
sys.stdout.write("\t Anonymously Used:\t\t%s\t%s\n" % (
arc['cache_hits_by_cache_list']['anonymously_used']['per'],
arc['cache_hits_by_cache_list']['anonymously_used']['num'],
)
)
sys.stdout.write("\t Most Recently Used:\t\t%s\t%s\n" % (
arc['most_recently_used']['per'],
arc['most_recently_used']['num'],
)
)
sys.stdout.write("\t Most Frequently Used:\t\t%s\t%s\n" % (
arc['most_frequently_used']['per'],
arc['most_frequently_used']['num'],
)
)
sys.stdout.write("\t Most Recently Used Ghost:\t%s\t%s\n" % (
arc['most_recently_used_ghost']['per'],
arc['most_recently_used_ghost']['num'],
)
)
sys.stdout.write("\t Most Frequently Used Ghost:\t%s\t%s\n" % (
arc['most_frequently_used_ghost']['per'],
arc['most_frequently_used_ghost']['num'],
)
)
sys.stdout.write("\n\tCACHE HITS BY DATA TYPE:\n")
sys.stdout.write("\t Demand Data:\t\t\t%s\t%s\n" % (
arc["cache_hits_by_data_type"]['demand_data']['per'],
arc["cache_hits_by_data_type"]['demand_data']['num'],
)
)
sys.stdout.write("\t Prefetch Data:\t\t%s\t%s\n" % (
arc["cache_hits_by_data_type"]['prefetch_data']['per'],
arc["cache_hits_by_data_type"]['prefetch_data']['num'],
)
)
sys.stdout.write("\t Demand Metadata:\t\t%s\t%s\n" % (
arc["cache_hits_by_data_type"]['demand_metadata']['per'],
arc["cache_hits_by_data_type"]['demand_metadata']['num'],
)
)
sys.stdout.write("\t Prefetch Metadata:\t\t%s\t%s\n" % (
arc["cache_hits_by_data_type"]['prefetch_metadata']['per'],
arc["cache_hits_by_data_type"]['prefetch_metadata']['num'],
)
)
sys.stdout.write("\n\tCACHE MISSES BY DATA TYPE:\n")
sys.stdout.write("\t Demand Data:\t\t\t%s\t%s\n" % (
arc["cache_misses_by_data_type"]['demand_data']['per'],
arc["cache_misses_by_data_type"]['demand_data']['num'],
)
)
sys.stdout.write("\t Prefetch Data:\t\t%s\t%s\n" % (
arc["cache_misses_by_data_type"]['prefetch_data']['per'],
arc["cache_misses_by_data_type"]['prefetch_data']['num'],
)
)
sys.stdout.write("\t Demand Metadata:\t\t%s\t%s\n" % (
arc["cache_misses_by_data_type"]['demand_metadata']['per'],
arc["cache_misses_by_data_type"]['demand_metadata']['num'],
)
)
sys.stdout.write("\t Prefetch Metadata:\t\t%s\t%s\n" % (
arc["cache_misses_by_data_type"]['prefetch_metadata']['per'],
arc["cache_misses_by_data_type"]['prefetch_metadata']['num'],
)
)
def get_l2arc_summary(Kstat):
"""Collection information on the L2ARC"""
output = {}
l2_abort_lowmem = Kstat["kstat.zfs.misc.arcstats.l2_abort_lowmem"]
l2_cksum_bad = Kstat["kstat.zfs.misc.arcstats.l2_cksum_bad"]
l2_evict_lock_retry = Kstat["kstat.zfs.misc.arcstats.l2_evict_lock_retry"]
l2_evict_reading = Kstat["kstat.zfs.misc.arcstats.l2_evict_reading"]
l2_feeds = Kstat["kstat.zfs.misc.arcstats.l2_feeds"]
l2_free_on_write = Kstat["kstat.zfs.misc.arcstats.l2_free_on_write"]
l2_hdr_size = Kstat["kstat.zfs.misc.arcstats.l2_hdr_size"]
l2_hits = Kstat["kstat.zfs.misc.arcstats.l2_hits"]
l2_io_error = Kstat["kstat.zfs.misc.arcstats.l2_io_error"]
l2_misses = Kstat["kstat.zfs.misc.arcstats.l2_misses"]
l2_rw_clash = Kstat["kstat.zfs.misc.arcstats.l2_rw_clash"]
l2_size = Kstat["kstat.zfs.misc.arcstats.l2_size"]
l2_asize = Kstat["kstat.zfs.misc.arcstats.l2_asize"]
l2_writes_done = Kstat["kstat.zfs.misc.arcstats.l2_writes_done"]
l2_writes_error = Kstat["kstat.zfs.misc.arcstats.l2_writes_error"]
l2_writes_sent = Kstat["kstat.zfs.misc.arcstats.l2_writes_sent"]
l2_mfu_asize = Kstat["kstat.zfs.misc.arcstats.l2_mfu_asize"]
l2_mru_asize = Kstat["kstat.zfs.misc.arcstats.l2_mru_asize"]
l2_prefetch_asize = Kstat["kstat.zfs.misc.arcstats.l2_prefetch_asize"]
l2_bufc_data_asize = Kstat["kstat.zfs.misc.arcstats.l2_bufc_data_asize"]
l2_bufc_metadata_asize = Kstat["kstat.zfs.misc.arcstats.l2_bufc_metadata_asize"]
l2_access_total = (l2_hits + l2_misses)
output['l2_health_count'] = (l2_writes_error + l2_cksum_bad + l2_io_error)
output['l2_access_total'] = l2_access_total
output['l2_size'] = l2_size
output['l2_asize'] = l2_asize
if l2_size > 0 and l2_access_total > 0:
if output['l2_health_count'] > 0:
output["health"] = "DEGRADED"
else:
output["health"] = "HEALTHY"
output["low_memory_aborts"] = fHits(l2_abort_lowmem)
output["free_on_write"] = fHits(l2_free_on_write)
output["rw_clashes"] = fHits(l2_rw_clash)
output["bad_checksums"] = fHits(l2_cksum_bad)
output["io_errors"] = fHits(l2_io_error)
output["l2_arc_size"] = {}
output["l2_arc_size"]["adaptive"] = fBytes(l2_size)
output["l2_arc_size"]["actual"] = {
'per': fPerc(l2_asize, l2_size),
'num': fBytes(l2_asize)
}
output["l2_arc_size"]["head_size"] = {
'per': fPerc(l2_hdr_size, l2_size),
'num': fBytes(l2_hdr_size),
}
output["l2_arc_size"]["mfu_asize"] = {
'per': fPerc(l2_mfu_asize, l2_asize),
'num': fBytes(l2_mfu_asize),
}
output["l2_arc_size"]["mru_asize"] = {
'per': fPerc(l2_mru_asize, l2_asize),
'num': fBytes(l2_mru_asize),
}
output["l2_arc_size"]["prefetch_asize"] = {
'per': fPerc(l2_prefetch_asize, l2_asize),
'num': fBytes(l2_prefetch_asize),
}
output["l2_arc_size"]["bufc_data_asize"] = {
'per': fPerc(l2_bufc_data_asize, l2_asize),
'num': fBytes(l2_bufc_data_asize),
}
output["l2_arc_size"]["bufc_metadata_asize"] = {
'per': fPerc(l2_bufc_metadata_asize, l2_asize),
'num': fBytes(l2_bufc_metadata_asize),
}
output["l2_arc_evicts"] = {}
output["l2_arc_evicts"]['lock_retries'] = fHits(l2_evict_lock_retry)
output["l2_arc_evicts"]['reading'] = fHits(l2_evict_reading)
output['l2_arc_breakdown'] = {}
output['l2_arc_breakdown']['value'] = fHits(l2_access_total)
output['l2_arc_breakdown']['hit_ratio'] = {
'per': fPerc(l2_hits, l2_access_total),
'num': fHits(l2_hits),
}
output['l2_arc_breakdown']['miss_ratio'] = {
'per': fPerc(l2_misses, l2_access_total),
'num': fHits(l2_misses),
}
output['l2_arc_breakdown']['feeds'] = fHits(l2_feeds)
output['l2_arc_buffer'] = {}
output['l2_arc_writes'] = {}
output['l2_writes_done'] = l2_writes_done
output['l2_writes_sent'] = l2_writes_sent
if l2_writes_done != l2_writes_sent:
output['l2_arc_writes']['writes_sent'] = {
'value': "FAULTED",
'num': fHits(l2_writes_sent),
}
output['l2_arc_writes']['done_ratio'] = {
'per': fPerc(l2_writes_done, l2_writes_sent),
'num': fHits(l2_writes_done),
}
output['l2_arc_writes']['error_ratio'] = {
'per': fPerc(l2_writes_error, l2_writes_sent),
'num': fHits(l2_writes_error),
}
else:
output['l2_arc_writes']['writes_sent'] = {
'per': fPerc(100),
'num': fHits(l2_writes_sent),
}
return output
def _l2arc_summary(Kstat):
"""Print information on the L2ARC"""
arc = get_l2arc_summary(Kstat)
if arc['l2_size'] > 0 and arc['l2_access_total'] > 0:
sys.stdout.write("L2 ARC Summary: ")
if arc['l2_health_count'] > 0:
sys.stdout.write("(DEGRADED)\n")
else:
sys.stdout.write("(HEALTHY)\n")
sys.stdout.write("\tLow Memory Aborts:\t\t\t%s\n" %
arc['low_memory_aborts'])
sys.stdout.write("\tFree on Write:\t\t\t\t%s\n" % arc['free_on_write'])
sys.stdout.write("\tR/W Clashes:\t\t\t\t%s\n" % arc['rw_clashes'])
sys.stdout.write("\tBad Checksums:\t\t\t\t%s\n" % arc['bad_checksums'])
sys.stdout.write("\tIO Errors:\t\t\t\t%s\n" % arc['io_errors'])
sys.stdout.write("\n")
sys.stdout.write("L2 ARC Size: (Adaptive)\t\t\t\t%s\n" %
arc["l2_arc_size"]["adaptive"])
sys.stdout.write("\tCompressed:\t\t\t%s\t%s\n" % (
arc["l2_arc_size"]["actual"]["per"],
arc["l2_arc_size"]["actual"]["num"],
)
)
sys.stdout.write("\tHeader Size:\t\t\t%s\t%s\n" % (
arc["l2_arc_size"]["head_size"]["per"],
arc["l2_arc_size"]["head_size"]["num"],
)
)
sys.stdout.write("\tMFU Alloc. Size:\t\t%s\t%s\n" % (
arc["l2_arc_size"]["mfu_asize"]["per"],
arc["l2_arc_size"]["mfu_asize"]["num"],
)
)
sys.stdout.write("\tMRU Alloc. Size:\t\t%s\t%s\n" % (
arc["l2_arc_size"]["mru_asize"]["per"],
arc["l2_arc_size"]["mru_asize"]["num"],
)
)
sys.stdout.write("\tPrefetch Alloc. Size:\t\t%s\t%s\n" % (
arc["l2_arc_size"]["prefetch_asize"]["per"],
arc["l2_arc_size"]["prefetch_asize"]["num"],
)
)
sys.stdout.write("\tData (buf content) Alloc. Size:\t%s\t%s\n" % (
arc["l2_arc_size"]["bufc_data_asize"]["per"],
arc["l2_arc_size"]["bufc_data_asize"]["num"],
)
)
sys.stdout.write("\tMetadata (buf content) Size:\t%s\t%s\n" % (
arc["l2_arc_size"]["bufc_metadata_asize"]["per"],
arc["l2_arc_size"]["bufc_metadata_asize"]["num"],
)
)
sys.stdout.write("\n")
if arc["l2_arc_evicts"]['lock_retries'] != '0' or \
arc["l2_arc_evicts"]["reading"] != '0':
sys.stdout.write("L2 ARC Evictions:\n")
sys.stdout.write("\tLock Retries:\t\t\t\t%s\n" %
arc["l2_arc_evicts"]['lock_retries'])
sys.stdout.write("\tUpon Reading:\t\t\t\t%s\n" %
arc["l2_arc_evicts"]["reading"])
sys.stdout.write("\n")
sys.stdout.write("L2 ARC Breakdown:\t\t\t\t%s\n" %
arc['l2_arc_breakdown']['value'])
sys.stdout.write("\tHit Ratio:\t\t\t%s\t%s\n" % (
arc['l2_arc_breakdown']['hit_ratio']['per'],
arc['l2_arc_breakdown']['hit_ratio']['num'],
)
)
sys.stdout.write("\tMiss Ratio:\t\t\t%s\t%s\n" % (
arc['l2_arc_breakdown']['miss_ratio']['per'],
arc['l2_arc_breakdown']['miss_ratio']['num'],
)
)
sys.stdout.write("\tFeeds:\t\t\t\t\t%s\n" %
arc['l2_arc_breakdown']['feeds'])
sys.stdout.write("\n")
sys.stdout.write("L2 ARC Writes:\n")
if arc['l2_writes_done'] != arc['l2_writes_sent']:
sys.stdout.write("\tWrites Sent: (%s)\t\t\t\t%s\n" % (
arc['l2_arc_writes']['writes_sent']['value'],
arc['l2_arc_writes']['writes_sent']['num'],
)
)
sys.stdout.write("\t Done Ratio:\t\t\t%s\t%s\n" % (
arc['l2_arc_writes']['done_ratio']['per'],
arc['l2_arc_writes']['done_ratio']['num'],
)
)
sys.stdout.write("\t Error Ratio:\t\t\t%s\t%s\n" % (
arc['l2_arc_writes']['error_ratio']['per'],
arc['l2_arc_writes']['error_ratio']['num'],
)
)
else:
sys.stdout.write("\tWrites Sent:\t\t\t%s\t%s\n" % (
arc['l2_arc_writes']['writes_sent']['per'],
arc['l2_arc_writes']['writes_sent']['num'],
)
)
def get_dmu_summary(Kstat):
"""Collect information on the DMU"""
output = {}
zfetch_hits = Kstat["kstat.zfs.misc.zfetchstats.hits"]
zfetch_misses = Kstat["kstat.zfs.misc.zfetchstats.misses"]
zfetch_access_total = (zfetch_hits + zfetch_misses)
output['zfetch_access_total'] = zfetch_access_total
if zfetch_access_total > 0:
output['dmu'] = {}
output['dmu']['efficiency'] = {}
output['dmu']['efficiency']['value'] = fHits(zfetch_access_total)
output['dmu']['efficiency']['hit_ratio'] = {
'per': fPerc(zfetch_hits, zfetch_access_total),
'num': fHits(zfetch_hits),
}
output['dmu']['efficiency']['miss_ratio'] = {
'per': fPerc(zfetch_misses, zfetch_access_total),
'num': fHits(zfetch_misses),
}
return output
def _dmu_summary(Kstat):
"""Print information on the DMU"""
arc = get_dmu_summary(Kstat)
if arc['zfetch_access_total'] > 0:
sys.stdout.write("DMU Prefetch Efficiency:\t\t\t\t\t%s\n" %
arc['dmu']['efficiency']['value'])
sys.stdout.write("\tHit Ratio:\t\t\t%s\t%s\n" % (
arc['dmu']['efficiency']['hit_ratio']['per'],
arc['dmu']['efficiency']['hit_ratio']['num'],
)
)
sys.stdout.write("\tMiss Ratio:\t\t\t%s\t%s\n" % (
arc['dmu']['efficiency']['miss_ratio']['per'],
arc['dmu']['efficiency']['miss_ratio']['num'],
)
)
sys.stdout.write("\n")
def get_vdev_summary(Kstat):
"""Collect information on the VDEVs"""
output = {}
vdev_cache_delegations = \
Kstat["kstat.zfs.misc.vdev_cache_stats.delegations"]
vdev_cache_misses = Kstat["kstat.zfs.misc.vdev_cache_stats.misses"]
vdev_cache_hits = Kstat["kstat.zfs.misc.vdev_cache_stats.hits"]
vdev_cache_total = (vdev_cache_misses + vdev_cache_hits +
vdev_cache_delegations)
output['vdev_cache_total'] = vdev_cache_total
if vdev_cache_total > 0:
output['summary'] = fHits(vdev_cache_total)
output['hit_ratio'] = {
'per': fPerc(vdev_cache_hits, vdev_cache_total),
'num': fHits(vdev_cache_hits),
}
output['miss_ratio'] = {
'per': fPerc(vdev_cache_misses, vdev_cache_total),
'num': fHits(vdev_cache_misses),
}
output['delegations'] = {
'per': fPerc(vdev_cache_delegations, vdev_cache_total),
'num': fHits(vdev_cache_delegations),
}
return output
def _vdev_summary(Kstat):
"""Print information on the VDEVs"""
arc = get_vdev_summary(Kstat)
if arc['vdev_cache_total'] > 0:
sys.stdout.write("VDEV Cache Summary:\t\t\t\t%s\n" % arc['summary'])
sys.stdout.write("\tHit Ratio:\t\t\t%s\t%s\n" % (
arc['hit_ratio']['per'],
arc['hit_ratio']['num'],
))
sys.stdout.write("\tMiss Ratio:\t\t\t%s\t%s\n" % (
arc['miss_ratio']['per'],
arc['miss_ratio']['num'],
))
sys.stdout.write("\tDelegations:\t\t\t%s\t%s\n" % (
arc['delegations']['per'],
arc['delegations']['num'],
))
def _tunable_summary(Kstat):
"""Print information on tunables, including descriptions if requested"""
global show_tunable_descriptions
global alternate_tunable_layout
tunables = load_tunables()
descriptions = {}
if show_tunable_descriptions:
command = ["/sbin/modinfo", "zfs", "-0"]
try:
p = Popen(command, stdin=PIPE, stdout=PIPE,
stderr=PIPE, shell=False, close_fds=True)
p.wait()
# By default, Python 2 returns a string as the first element of the
# tuple from p.communicate(), while Python 3 returns bytes which
# must be decoded first. The better way to do this would be with
# subprocess.run() or at least .check_output(), but this fails on
# CentOS 6 because of its old version of Python 2
desc = bytes.decode(p.communicate()[0])
description_list = desc.strip().split('\0')
if p.returncode == 0:
for tunable in description_list:
if tunable[0:5] == 'parm:':
tunable = tunable[5:].strip()
name, description = tunable.split(':', 1)
if not description:
description = "Description unavailable"
descriptions[name] = description
else:
sys.stderr.write("%s: '%s' exited with code %i\n" %
(sys.argv[0], command[0], p.returncode))
sys.stderr.write("Tunable descriptions will be disabled.\n")
except OSError as e:
sys.stderr.write("%s: Cannot run '%s': %s\n" %
(sys.argv[0], command[0], e.strerror))
sys.stderr.write("Tunable descriptions will be disabled.\n")
sys.stdout.write("ZFS Tunables:\n")
if alternate_tunable_layout:
fmt = "\t%s=%s\n"
else:
fmt = "\t%-50s%s\n"
for name in sorted(tunables.keys()):
if show_tunable_descriptions and name in descriptions:
sys.stdout.write("\t# %s\n" % descriptions[name])
sys.stdout.write(fmt % (name, tunables[name]))
unSub = [
_arc_summary,
_arc_efficiency,
_l2arc_summary,
_dmu_summary,
_vdev_summary,
_tunable_summary
]
def zfs_header():
"""Print title string with date"""
daydate = time.strftime('%a %b %d %H:%M:%S %Y')
sys.stdout.write('\n'+'-'*72+'\n')
sys.stdout.write('ZFS Subsystem Report\t\t\t\t%s' % daydate)
sys.stdout.write('\n')
def usage():
"""Print usage information"""
sys.stdout.write("Usage: arc_summary [-h] [-a] [-d] [-p PAGE]\n\n")
sys.stdout.write("\t -h, --help : "
"Print this help message and exit\n")
sys.stdout.write("\t -a, --alternate : "
"Show an alternate sysctl layout\n")
sys.stdout.write("\t -d, --description : "
"Show the sysctl descriptions\n")
sys.stdout.write("\t -p PAGE, --page=PAGE : "
"Select a single output page to display,\n")
sys.stdout.write("\t "
"should be an integer between 1 and " +
str(len(unSub)) + "\n\n")
sys.stdout.write("Examples:\n")
sys.stdout.write("\tarc_summary -a\n")
sys.stdout.write("\tarc_summary -p 4\n")
sys.stdout.write("\tarc_summary -ad\n")
sys.stdout.write("\tarc_summary --page=2\n")
def main():
"""Main function"""
global show_tunable_descriptions
global alternate_tunable_layout
try:
opts, args = getopt.getopt(
sys.argv[1:],
"adp:h", ["alternate", "description", "page=", "help"]
)
except getopt.error as e:
sys.stderr.write("Error: %s\n" % e.msg)
usage()
sys.exit(1)
args = {}
for opt, arg in opts:
if opt in ('-a', '--alternate'):
args['a'] = True
if opt in ('-d', '--description'):
args['d'] = True
if opt in ('-p', '--page'):
args['p'] = arg
if opt in ('-h', '--help'):
usage()
sys.exit(0)
Kstat = get_Kstat()
alternate_tunable_layout = 'a' in args
show_tunable_descriptions = 'd' in args
pages = []
if 'p' in args:
try:
pages.append(unSub[int(args['p']) - 1])
except IndexError:
sys.stderr.write('the argument to -p must be between 1 and ' +
str(len(unSub)) + '\n')
sys.exit(1)
else:
pages = unSub
zfs_header()
for page in pages:
page(Kstat)
sys.stdout.write("\n")
if __name__ == '__main__':
main()
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