SMARTD(8) SMART Monitoring Tools SMARTD(8)
smartd - SMART Disk Monitoring Daemon
[This man page is generated for the Linux version of smartmontools. It
does not contain info specific to other platforms.]
smartd is a daemon that monitors the Self-Monitoring, Analysis and
Reporting Technology (SMART) system built into most ATA/SATA and
SCSI/SAS hard drives and solid-state drives. The purpose of SMART is
to monitor the reliability of the hard drive and predict drive fail-
ures, and to carry out different types of drive self-tests. This ver-
sion of smartd is compatible with ACS-3, ACS-2, ATA8-ACS, ATA/ATAPI-7
and earlier standards (see REFERENCES below).
smartd will attempt to enable SMART monitoring on ATA devices (equiva-
lent to smartctl -s on) and polls these and SCSI devices every 30 min-
utes (configurable), logging SMART errors and changes of SMART
Attributes via the SYSLOG interface. The default location for these
SYSLOG notifications and warnings is system-dependent (typically
/var/log/messages or /var/log/syslog). To change this default loca-
tion, please see the '-l' command-line option described below.
In addition to logging to a file, smartd can also be configured to send
email warnings if problems are detected. Depending upon the type of
problem, you may want to run self-tests on the disk, back up the disk,
replace the disk, or use a manufacturer's utility to force reallocation
of bad or unreadable disk sectors. If disk problems are detected,
please see the smartctl manual page and the smartmontools web page/FAQ
for further guidance.
If you send a USR1 signal to smartd it will immediately check the sta-
tus of the disks, and then return to polling the disks every 30 min-
utes. See the '-i' option below for additional details.
smartd can be configured at start-up using the configuration file
/etc/smartd.conf (Windows: EXEDIR/smartd.conf). If the configuration
file is subsequently modified, smartd can be told to re-read the con-
figuration file by sending it a HUP signal, for example with the com-
killall -HUP smartd.
On startup, if smartd finds a syntax error in the configuration file,
it will print an error message and then exit. However if smartd is
already running, then is told with a HUP signal to re-read the configu-
ration file, and then find a syntax error in this file, it will print
an error message and then continue, ignoring the contents of the
(faulty) configuration file, as if the HUP signal had never been
When smartd is running in debug mode, the INT signal (normally gener-
ated from a shell with CONTROL-C) is treated in the same way as a HUP
signal: it makes smartd reload its configuration file. To exit smartd
On startup, in the absence of the configuration file /etc/smartd.conf,
the smartd daemon first scans for all devices that support SMART. The
scanning is done as follows:
LINUX: Examine all entries "/dev/hd[a-t]" for IDE/ATA devices, and
"/dev/sd[a-z]", "/dev/sd[a-c][a-z]" for ATA/SATA or SCSI/SAS
devices. Disks behind RAID controllers are not included.
[NEW EXPERIMENTAL SMARTD FEATURE] If directive '-d nvme' is
specified, examine all entries "/dev/nvme[0-99]" for NVMe
smartd then monitors for all possible SMART errors (corresponding to
the '-a' Directive in the configuration file; see the smartd.conf(5)
-A PREFIX, --attributelog=PREFIX
Writes smartd attribute information (normalized and raw
attribute values) to files 'PREFIX''MODEL-SERIAL.ata.csv' or
'PREFIX''VENDOR-MODEL-SERIAL.scsi.csv'. At each check cycle
attributes are logged as a line of semicolon separated triplets
of the form "attribute-ID;attribute-norm-value;attribute-raw-
value;". For SCSI devices error counters and temperature
recorded in the form "counter-name;counter-value;" Each line is
led by a date string of the form "yyyy-mm-dd HH:MM:SS" (in UTC).
If this option is not specified, attribute information is writ-
ten to files '/var/lib/smartmontools/attr-
log.MODEL-SERIAL.ata.csv'. To disable attribute log files,
specify this option with an empty string argument: '-A ""'.
MODEL and SERIAL are build from drive identify information,
invalid characters are replaced by underline.
If the PREFIX has the form '/path/dir/' (e.g.
'/var/lib/smartd/'), then files 'MODEL-SERIAL.ata.csv' are cre-
ated in directory '/path/dir'. If the PREFIX has the form
'/path/name' (e.g. '/var/lib/misc/attrlog-'), then files 'nameM-
ODEL-SERIAL.ata.csv' are created in directory '/path/'. The
path must be absolute, except if debug mode is enabled.
-B [+]FILE, --drivedb=[+]FILE
[ATA only] Read the drive database from FILE. The new database
replaces the built in database by default. If '+' is specified,
then the new entries prepend the built in entries. Please see
the smartctl(8) man page for further details.
-c FILE, --configfile=FILE
Read smartd configuration Directives from FILE, instead of from
the default location /etc/smartd.conf (Windows:
EXEDIR/smartd.conf). If FILE does not exist, then smartd will
print an error message and exit with nonzero status. Thus, '-c
/etc/smartd.conf' can be used to verify the existence of the
default configuration file.
By using '-' for FILE, the configuration is read from standard
input. This is useful for commands like:
echo /dev/sdb -m user@home -M test | smartd -c - -q onecheck
to perform quick and simple checks without a configuration file.
[Linux only] Use libcap-ng to drop unneeded Linux process capa-
bilities(7). The following capabilities are kept:
CAP_SYS_ADMIN, CAP_SYS_RAWIO, CAP_MKNOD.
Warning: Mail notification does not work when used.
Runs smartd in "debug" mode. In this mode, it displays status
information to STDOUT rather than logging it to SYSLOG and does
not fork(2) into the background and detach from the controlling
terminal. In this mode, smartd also prints more verbose infor-
mation about what it is doing than when operating in "daemon"
mode. In this mode, the INT signal (normally generated from a
terminal with CONTROL-C) makes smartd reload its configuration
file. Please use CONTROL-\ to exit
Prints a list (to STDOUT) of all the possible Directives which
may appear in the configuration file /etc/smartd.conf, and then
exits. These Directives are described in the smartd.conf(5) man
page. They may appear in the configuration file following the
-h, --help, --usage
Prints usage message to STDOUT and exits.
-i N, --interval=N
Sets the interval between disk checks to N seconds, where N is a
decimal integer. The minimum allowed value is ten and the maxi-
mum is the largest positive integer that can be represented on
your system (often 2^31-1). The default is 1800 seconds.
Note that the superuser can make smartd check the status of the
disks at any time by sending it the SIGUSR1 signal, for example
with the command:
kill -SIGUSR1 <pid>
where <pid> is the process id number of smartd. One may also
killall -USR1 smartd
for the same purpose.
-l FACILITY, --logfacility=FACILITY
Uses syslog facility FACILITY to log the messages from smartd.
Here FACILITY is one of local0, local1, ..., local7, or daemon
[default]. If this command-line option is not used, then by
default messages from smartd are logged to the facility daemon.
If you would like to have smartd messages logged somewhere other
than the default location, include (for example) '-l local3' in
its start up argument list. Tell the syslog daemon to log all
messages from facility local3 to (for example)
For more detailed information, please refer to the man pages for
the local syslog daemon, typically syslogd(8), syslog-ng(8) or
Do not fork into background; this is useful when executed from
modern init methods like initng, minit, supervise or systemd.
-p NAME, --pidfile=NAME
Writes pidfile NAME containing the smartd Process ID number
(PID). To avoid symlink attacks make sure the directory to
which pidfile is written is only writable for root. Without
this option, or if the --debug option is given, no PID file is
written on startup. If smartd is killed with a maskable signal
then the pidfile is removed.
-q WHEN, --quit=WHEN
Specifies when, if ever, smartd should exit. The valid argu-
ments are to this option are:
nodev - Exit if there are no devices to monitor, or if any
errors are found at startup in the configuration file. This is
errors - Exit if there are no devices to monitor, or if any
errors are found in the configuration file /etc/smartd.conf at
startup or whenever it is reloaded.
nodevstartup - Exit if there are no devices to monitor at
startup. But continue to run if no devices are found whenever
the configuration file is reloaded.
never - Only exit if a fatal error occurs (no remaining system
memory, invalid command line arguments). In this mode, even if
there are no devices to monitor, or if the configuration file
/etc/smartd.conf has errors, smartd will continue to run, wait-
ing to load a configuration file listing valid devices.
onecheck - Start smartd in debug mode, then register devices,
then check device's SMART status once, and then exit with zero
exit status if all of these steps worked correctly.
This last option is intended for 'distribution-writers' who want
to create automated scripts to determine whether or not to auto-
matically start up smartd after installing smartmontools. After
starting smartd with this command-line option, the distribu-
tion's install scripts should wait a reasonable length of time
(say ten seconds). If smartd has not exited with zero status by
that time, the script should send smartd a SIGTERM or SIGKILL
and assume that smartd will not operate correctly on the host.
Conversely, if smartd exits with zero status, then it is safe to
run smartd in normal daemon mode. If smartd is unable to monitor
any devices or encounters other problems then it will return
with non-zero exit status.
showtests - Start smartd in debug mode, then register devices,
then write a list of future scheduled self tests to stdout, and
then exit with zero exit status if all of these steps worked
correctly. Device's SMART status is not checked.
This option is intended to test whether the '-s REGEX' direc-
tives in smartd.conf will have the desired effect. The output
lists the next test schedules, limited to 5 tests per type and
device. This is followed by a summary of all tests of each
device within the next 90 days.
-r TYPE, --report=TYPE
Intended primarily to help smartmontools developers understand
the behavior of smartmontools on non-conforming or poorly-con-
forming hardware. This option reports details of smartd trans-
actions with the device. The option can be used multiple times.
When used just once, it shows a record of the ioctl() transac-
tions with the device. When used more than once, the detail of
these ioctl() transactions are reported in greater detail. The
valid arguments to this option are:
ioctl - report all ioctl() transactions.
ataioctl - report only ioctl() transactions with ATA devices.
scsiioctl - report only ioctl() transactions with SCSI devices.
nvmeioctl - [FreeBSD, Linux, Windows and Cygwin only] [NEW
EXPERIMENTAL SMARTD FEATURE] report only ioctl() transactions
with NVMe devices.
Any argument may include a positive integer to specify the level
of detail that should be reported. The argument should be fol-
lowed by a comma then the integer with no spaces. For example,
ataioctl,2 The default level is 1, so '-r ataioctl,1' and '-r
ataioctl' are equivalent.
-s PREFIX, --savestates=PREFIX
Reads/writes smartd state information from/to files 'PRE-
FIX''MODEL-SERIAL.ata.state' or 'PREFIX''VEN-
DOR-MODEL-SERIAL.scsi.state'. This preserves SMART attributes,
drive min and max temperatures (-W directive), info about last
sent warning email (-m directive), and the time of next check of
the self-test REGEXP (-s directive) across boot cycles.
If this option is not specified, state information is maintained
in files '/var/lib/smartmontools/smartd.MODEL-SERIAL.ata.state'
for ATA devices and '/var/lib/smartmontools/smartd.VEN-
DOR-MODEL-SERIAL.scsi.state' for SCSI devices. To disable state
files, specify this option with an empty string argument: '-s
""'. MODEL and SERIAL are build from drive identify informa-
tion, invalid characters are replaced by underline.
If the PREFIX has the form '/path/dir/' (e.g.
'/var/lib/smartd/'), then files 'MODEL-SERIAL.ata.state' are
created in directory '/path/dir'. If the PREFIX has the form
'/path/name' (e.g. '/var/lib/misc/smartd-'), then files 'nameMO-
DEL-SERIAL.ata.state' are created in directory '/path/'. The
path must be absolute, except if debug mode is enabled.
The state information files are read on smartd startup. The
files are always (re)written after reading the configuration
file, before rereading the configuration file (SIGHUP), before
smartd shutdown, and after a check forced by SIGUSR1. After a
normal check cycle, a file is only rewritten if an important
change (which usually results in a SYSLOG output) occurred.
-w PATH, --warnexec=PATH
Run the executable PATH instead of the default script when
smartd needs to send warning messages. PATH must point to an
executable binary file or script. The default script is
-V, --version, --license, --copyright
Prints version, copyright, license, home page and SVN revision
information for your copy of smartd to STDOUT and then exits.
Please include this information if you are reporting bugs or
Runs the daemon in forked mode. This is the normal way to run smartd.
Entries are logged to SYSLOG.
smartd -d -i 30
Run in foreground (debug) mode, checking the disk status every 30 sec-
smartd -q onecheck
Registers devices, and checks the status of the devices exactly once.
The exit status (the shell $? variable) will be zero if all went well,
and nonzero if no devices were detected or some other problem was
The syntax of the smartd.conf(5) file is discussed separately.
smartd will make log entries at loglevel LOG_INFO if the Normalized
SMART Attribute values have changed, as reported using the '-t', '-p',
or '-u' Directives. For example:
'Device: /dev/sda, SMART Attribute: 194 Temperature_Celsius changed from 94 to 93'
Note that in this message, the value given is the 'Normalized' not the
'Raw' Attribute value (the disk temperature in this case is about 22
Celsius). The '-R' and '-r' Directives modify this behavior, so that
the information is printed with the Raw values as well, for example:
'Device: /dev/sda, SMART Attribute: 194 Temperature_Celsius changed from 94 [Raw 22] to 93 [Raw 23]'
Here the Raw values are the actual disk temperatures in Celsius. The
way in which the Raw values are printed, and the names under which the
Attributes are reported, is governed by the various '-v Num,Descrip-
tion' Directives described previously.
Please see the smartctl manual page for further explanation of the dif-
ferences between Normalized and Raw Attribute values.
smartd will make log entries at loglevel LOG_CRIT if a SMART Attribute
has failed, for example:
'Device: /dev/sdc, Failed SMART Attribute: 5 Reallocated_Sector_Ct'
This loglevel is used for reporting enabled by the '-H', -f',
'-l selftest', and '-l error' Directives. Entries reporting failure of
SMART Prefailure Attributes should not be ignored: they mean that the
disk is failing. Use the smartctl utility to investigate.
LOG TIMESTAMP TIMEZONE
When smartd makes log entries, these are time-stamped. The time stamps
are in the computer's local time zone, which is generally set using
either the environment variable 'TZ' or using a time-zone file such as
/etc/localtime. You may wish to change the timezone while smartd is
running (for example, if you carry a laptop to a new time-zone and
don't reboot it). Due to a bug in the tzset(3) function of many unix
standard C libraries, the time-zone stamps of smartd might not change.
For some systems, smartd will work around this problem if the time-zone
is set using /etc/localtime. The work-around fails if the time-zone is
set using the 'TZ' variable (or a file that it points to).
The exit status (return value) of smartd can have the following values:
0: Daemon startup successful, or smartd was killed by a SIGTERM (or
in debug mode, a SIGQUIT).
1: Commandline did not parse.
2: There was a syntax error in the config file.
3: Forking the daemon failed.
4: Couldn't create PID file.
5: Config file does not exist (only returned in conjunction with
the '-c' option).
6: Config file exists, but cannot be read.
8: smartd ran out of memory during startup.
10: An inconsistency was found in smartd's internal data structures.
This should never happen. It must be due to either a coding or
compiler bug. Please report such failures to smartmontools
developers, see REPORTING BUGS below.
16: A device explicitly listed in /etc/smartd.conf can't be moni-
17: smartd didn't find any devices to monitor.
254: When in daemon mode, smartd received a SIGINT or SIGQUIT. (Note
that in debug mode, SIGINT has the same effect as SIGHUP, and
makes smartd reload its configuration file. SIGQUIT has the same
effect as SIGTERM and causes smartd to exit with zero exit sta-
132 and above
smartd was killed by a signal that is not explicitly listed
above. The exit status is then 128 plus the signal number. For
example if smartd is killed by SIGKILL (signal 9) then the exit
status is 137.
full path of this executable.
configuration file (see smartd.conf(5) man page).
script run on warnings (see '-M exec' directive on
smartd.conf(5) man page).
plugin directory for smartd warning script (see '-m' directive
on smartd.conf(5) man page).
drive database (see '-B' option).
optional local drive database (see '-B' option).
Bruce Allen (project initiator),
Christian Franke (project manager, Windows port and all sort of
Douglas Gilbert (SCSI subsystem),
Volker Kuhlmann (moderator of support and database mailing list),
Gabriele Pohl (wiki & development team support),
Alex Samorukov (FreeBSD port and more, new Trac wiki).
Many other individuals have made contributions and corrections, see
AUTHORS, ChangeLog and repository files.
The first smartmontools code was derived from the smartsuite package,
written by Michael Cornwell and Andre Hedrick.
To submit a bug report, create a ticket in smartmontools wiki:
Alternatively send the info to the smartmontools support mailing list:
Please see the following web site for more info: http://www.smartmon-
An introductory article about smartmontools is Monitoring Hard Disks
with SMART, by Bruce Allen, Linux Journal, January 2004, pages 74-77.
This is http://www.linuxjournal.com/article/6983 online.
If you would like to understand better how SMART works, and what it
does, a good place to start is with Sections 4.8 and 6.54 of the first
volume of the 'AT Attachment with Packet Interface-7' (ATA/ATAPI-7)
specification Revision 4b. This documents the SMART functionality
which the smartmontools utilities provide access to.
The functioning of SMART was originally defined by the SFF-8035i revi-
sion 2 and the SFF-8055i revision 1.4 specifications. These are publi-
cations of the Small Form Factors (SFF) Committee.
Links to these and other documents may be found on the Links page of
the smartmontools Wiki at http://www.smartmontools.org/wiki/Links .
smartmontools-6.6 2016-05-31 r4324
$Id: smartd.8.in 4299 2016-04-16 19:45:57Z chrfranke $
smartmontools-6.6 2016-05-31 SMARTD(8)
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