xref: /freebsd/share/man/man4/iscsi.4 (revision bd425507b7f4bc51903365d894f4eb85d645e0be)

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.Dd July 11, 2015
.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.
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 .
The
.Nm
subsystem is responsible for implementing the
.Qq Full Feature Phase
of the iSCSI protocol.
.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 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.