25b8ef953f
MFC after: 2 weeks
121 lines
3.8 KiB
Groff
121 lines
3.8 KiB
Groff
.\" Copyright (c) 2014 Edward Tomasz Napierala
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.Dd May 28, 2017
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.Dt ISCSI 4
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.Os
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.Sh NAME
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.Nm iscsi
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.Nd iSCSI initiator
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.Sh SYNOPSIS
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To compile this driver into the kernel,
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place the following line in the
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kernel configuration file:
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.Bd -ragged -offset indent
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.Cd "device iscsi"
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.Ed
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.Pp
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Alternatively, to load the driver as a
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module at boot time, place the following line in
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.Xr loader.conf 5 :
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.Bd -literal -offset indent
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iscsi_load="YES"
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.Ed
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.Sh DESCRIPTION
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The
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.Nm
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subsystem provides the kernel component of an iSCSI initiator,
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responsible for implementing the Full Feature Phase of the iSCSI protocol.
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The initiator is the iSCSI client, which connects to an iSCSI target,
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providing local access to a remote block device.
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The userland component is provided by
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.Xr iscsid 8
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and both the kernel and userland are configured using
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.Xr iscsictl 8 .
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.Sh SYSCTL VARIABLES
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The following variables are available as both
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.Xr sysctl 8
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variables and
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.Xr loader 8
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tunables:
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.Bl -tag -width indent
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.It Va kern.iscsi.debug
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Verbosity level for log messages from the
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.Nm
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driver.
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Set to 0 to disable logging or 1 to warn about potential problems.
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Larger values enable debugging output.
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Defaults to 1.
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.It Va kern.iscsi.ping_timeout
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The number of seconds to wait for the target to respond to a NOP-Out
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PDU.
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In the event that there is no response within that time the session gets
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forcibly restarted.
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Set to 0 to disable sending NOP-Out PDUs.
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Defaults to 5.
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.It Va kern.iscsi.iscsid_timeout
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The number of seconds to wait for
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.Xr iscsid 8
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to establish a session.
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After that time
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.Nm
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will abort and retry.
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Defaults to 60.
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.It Va kern.iscsi.login_timeout
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The number of seconds to wait for a login attempt to succeed.
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After that time
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.Nm
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will abort and retry.
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Defaults to 60.
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.It Va kern.iscsi.maxtags
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The maximum number of outstanding IO requests.
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Defaults to 255.
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.It Va kern.iscsi.fail_on_disconnection
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Controls the behavior after an iSCSI connection has been dropped due to
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network problems.
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When set to 1, a dropped connection causes the iSCSI device nodes
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to be destroyed.
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After reconnecting, they will be created again.
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By default, the device nodes are left intact.
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While the connection is down all input/output operations are suspended, to be
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retried after the connection is reestablished.
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.El
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.Sh SEE ALSO
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.Xr iser 4 ,
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.Xr iscsi.conf 5 ,
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.Xr iscsictl 8 ,
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.Xr iscsid 8
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.Sh HISTORY
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The
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.Nm
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subsystem first appeared in
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.Fx 10.0 .
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.Sh AUTHORS
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The
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.Nm
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subsystem was developed by
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.An Edward Tomasz Napierala Aq Mt trasz@FreeBSD.org
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under sponsorship from the FreeBSD Foundation.
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