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.\" Copyright (c) 2014 Edward Tomasz Napierala
.\" 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 THE 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 THE 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.
.\"
.\" $FreeBSD$
.Dd May 28, 2017
.Dt ISCSI 4
.Os
.Sh NAME
.Nm iscsi
.Nd iSCSI initiator
.Sh SYNOPSIS
To compile this driver into the kernel,
place the following line in the
kernel configuration file:
.Bd -ragged -offset indent
.Cd "device iscsi"
.Ed
.Pp
Alternatively, to load the driver as a
module at boot time, place the following line in
.Xr loader.conf 5 :
.Bd -literal -offset indent
iscsi_load="YES"
.Ed
.Sh DESCRIPTION
The
.Nm
subsystem provides the kernel component of an iSCSI initiator,
responsible for implementing the Full Feature Phase of the iSCSI protocol.
The initiator is the iSCSI client, which connects to an iSCSI target,
providing local access to a remote block device.
The userland component is provided by
.Xr iscsid 8
and both the kernel and userland are configured using
.Xr iscsictl 8 .
.Sh SYSCTL VARIABLES
The following variables are available as both
.Xr sysctl 8
variables and
.Xr loader 8
tunables:
.Bl -tag -width indent
.It Va kern.iscsi.debug
Verbosity level for log messages from the
.Nm
driver.
Set to 0 to disable logging or 1 to warn about potential problems.
Larger values enable debugging output.
Defaults to 1.
.It Va kern.iscsi.ping_timeout
The number of seconds to wait for the target to respond to a NOP-Out
PDU.
In the event that there is no response within that time the session gets
forcibly restarted.
Set to 0 to disable sending NOP-Out PDUs.
Defaults to 5.
.It Va kern.iscsi.iscsid_timeout
The number of seconds to wait for
.Xr iscsid 8
to establish a session.
After that time
.Nm
will abort and retry.
Defaults to 60.
.It Va kern.iscsi.login_timeout
The number of seconds to wait for a login attempt to succeed.
After that time
.Nm
will abort and retry.
Defaults to 60.
.It Va kern.iscsi.maxtags
The maximum number of outstanding IO requests.
Defaults to 255.
.It Va kern.iscsi.fail_on_disconnection
Controls the behavior after an iSCSI connection has been dropped due to
network problems.
When set to 1, a dropped connection causes the iSCSI device nodes
to be destroyed.
After reconnecting, they will be created again.
By default, the device nodes are left intact.
While the connection is down all input/output operations are suspended, to be
retried after the connection is reestablished.
.El
.Sh SEE ALSO
.Xr iser 4 ,
.Xr iscsi.conf 5 ,
.Xr iscsictl 8 ,
.Xr iscsid 8
.Sh HISTORY
The
.Nm
subsystem first appeared in
.Fx 10.0 .
.Sh AUTHORS
The
.Nm
subsystem was developed by
.An Edward Tomasz Napierala Aq Mt trasz@FreeBSD.org
under sponsorship from the FreeBSD Foundation.
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