.\"	$OpenBSD: esm.4,v 1.4 2007/05/31 19:19:54 jmc Exp $
.\"
.\" Copyright (c) 2005 David Gwynne <dlg@openbsd.org>
.\"
.\" Permission to use, copy, modify, and distribute this software for any
.\" purpose with or without fee is hereby granted, provided that the above
.\" copyright notice and this permission notice appear in all copies.
.\"
.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
.\" TORTIOUS ACTION, ARISING OUT OF
.\" PERFORMANCE OF THIS SOFTWARE.
.Dd $Mdocdate: May 31 2007 $
.Dt ESM 4 i386
.Os
.Sh NAME
.Nm esm
.Nd Dell Embedded Server Management
.Sh SYNOPSIS
.Cd "esm0 at mainbus?"
.Sh DESCRIPTION
The
.Nm
driver provides support for the monitoring of the environmental sensors
present in a variety of Dell servers.
The hardware monitoring is accessed via the
.Va hw.sensors
.Xr sysctl 8
variable.
.Pp
Devices compatible with the
.Nm
driver can provide an arbitrary set of sensors which may include the
following types:
.Bl -column "temperature" "Units" -offset indent
.It Sy "Sensor" Ta Sy "Units"
.It Li "temperature" Ta "uK"
.It Li "fan" Ta "RPM"
.It Li "volts" Ta "uVDC"
.El
.Pp
Sensor data is updated every 10 seconds.
.Pp
The Embedded Server Management framework has been replaced in more recent
Dell systems with the Intelligent Platform Management Interface.
Servers using the Intelligent Platform Management Interface may be
monitored by the
.Xr ipmi 4
driver.
.Sh WATCHDOG
ESM provides
.Xr watchdog 4
timer functionality.
Once configured, if the watchdog is not reset within
a certain period of time,
it will timeout and the server will reset.
The reset will occur regardless of the recoverability of the hang or crash.
.Pp
Example of enabling a watchdog:
.Pp
.Dl # sysctl kern.watchdog.period=10
.Pp
In this case if the watchdog is not reset,
it'll reboot the server after roughly 10 seconds.
.Pp
Example of disabling the watchdog:
.Pp
.Dl # sysctl kern.watchdog.period=0
.Sh SEE ALSO
.Xr intro 4 ,
.Xr ipmi 4 ,
.Xr watchdog 4 ,
.Xr sensorsd 8 ,
.Xr sysctl 8
.Sh HISTORY
The
.Nm
driver first appeared in
.Ox 3.9 .
.Sh AUTHORS
The
.Nm
driver was written by
.An Jordan Hargrave Aq jordan@openbsd.org
and
.An David Gwynne Aq dlg@openbsd.org .