- SMART Disk Monitoring Daemon
[This man page is generated for the Linux version of smartmontools. It does not
contain info specific to other platforms.]
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 failures, and to carry out
different types of drive self-tests. This version of smartd
compatible with ACS-3, ACS-2, ATA8-ACS, ATA/ATAPI-7 and earlier standards (see
will attempt to enable SMART monitoring on ATA devices (equivalent
to smartctl -s on
) and polls these and SCSI devices every 30 minutes
(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
). To change this default location, please see the
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
manual page and the smartmontools
web page/FAQ for
If you send a USR1
signal to smartd
it will immediately check the
status of the disks, and then return to polling the disks every 30 minutes.
See the ´-i´
option below for additional details.
can be configured at start-up using the configuration file
). If the
configuration file is subsequently modified, smartd
can be told to
re-read the configuration file by sending it a HUP
signal, for example
with the command:
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
running, then is told with a HUP
signal to re-read the configuration
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 received.
is running in debug mode, the INT
generated from a shell with CONTROL-C) is treated in the same way as a
signal: it makes smartd
reload its configuration file. To
On startup, in the absence of the configuration file /etc/smartd.conf
daemon first scans for all devices that support SMART. The
scanning is done as follows:
- 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
then monitors for all
possible SMART errors (corresponding
to the ´-a´
Directive in the configuration file; see the
(5) man page).
- -A PREFIX, --attributelog=PREFIX
- Writes smartd attribute information (normalized and
raw attribute values) to files
each check cycle attributes are logged as a line of semicolon separated
triplets of the form
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 written to files
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 created in directory
´/path/dir´. If the PREFIX has the form
´/path/name´ (e.g. ´/var/lib/misc/attrlog-´),
then files 'nameMODEL-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.
- -C, --capabilities
- [Linux only] Use libcap-ng to drop unneeded Linux process
capabilities(7). The following capabilities are kept:
CAP_SYS_ADMIN, CAP_SYS_RAWIO, CAP_MKNOD.
Warning: Mail notification does not work when used.
- -d, --debug
- 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
information 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
- -D, --showdirectives
- 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 device
- -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 maximum 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
kill -SIGUSR1 <pid>
where <pid> is the process id number of smartd. One may
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
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
- -n, --no-fork
- 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 arguments 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 the default.
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,
waiting 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
automatically start up smartd after installing smartmontools. After
starting smartd with this command-line option, the
distribution´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' directives 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-conforming hardware. This option reports details of smartd
transactions with the device. The option can be used multiple times. When
used just once, it shows a record of the ioctl() transactions 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
Any argument may include a positive integer to specify the level of detail
that should be reported. The argument should be followed 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
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
ATA devices and
for SCSI devices. To disable state files, specify this option with an
empty string argument: ´-s ""´. MODEL and SERIAL
are build from drive identify information, invalid characters are replaced
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 'nameMODEL-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)
- -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 seconds.
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 encountered.
The syntax of the smartd.conf
(5) file is discussed separately.
will make log entries at loglevel LOG_INFO
Normalized SMART Attribute values have changed, as reported using the
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´
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,Description´
Directives described previously.
Please see the smartctl
manual page for further explanation of the
differences between Normalized and Raw Attribute values.
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´,
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.
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
. You may wish to change the timezone while
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
of many unix standard C libraries, the time-zone stamps of smartd
not change. For some systems, smartd
will work around this problem
the time-zone is set using /etc/localtime
. The work-around
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:
- Daemon startup successful, or smartd was killed by a
SIGTERM (or in debug mode, a SIGQUIT).
- Commandline did not parse.
- There was a syntax error in the config file.
- Forking the daemon failed.
- Couldn´t create PID file.
- Config file does not exist (only returned in conjunction
with the ´-c´ option).
- Config file exists, but cannot be read.
- smartd ran out of memory during startup.
- 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.
- A device explicitly listed in /etc/smartd.conf
can´t be monitored.
- smartd didn´t find any devices to
- 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
- 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
- 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´
(project manager, Windows port and all sort of things),
(moderator of support and database mailing list),
(wiki & development team support),
(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:
An introductory article about smartmontools is Monitoring Hard Disks
, by Bruce Allen, Linux Journal, January 2004, pages 74-77. This
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
utilities provide access to.
The functioning of SMART was originally defined by the SFF-8035i revision 2 and
the SFF-8055i revision 1.4 specifications. These are publications of the Small
Form Factors (SFF) Committee.
Links to these and other documents may be found on the Links page of the
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 $