1.\" Copyright (c) 2013 Edward Tomasz Napierala 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 13.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 14.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23.\" SUCH DAMAGE. 24.\" 25.\" $FreeBSD$ 26.Dd August 9, 2015 27.Dt CTL 4 28.Os 29.Sh NAME 30.Nm ctl 31.Nd CAM Target Layer / iSCSI target 32.Sh SYNOPSIS 33To compile this driver into the kernel, 34place the following line in your 35kernel configuration file: 36.Bd -ragged -offset indent 37.Cd "device iscsi" 38.Cd "device ctl" 39.Ed 40.Pp 41Alternatively, to load the driver as a 42module at boot time, place the following line in 43.Xr loader.conf 5 : 44.Bd -literal -offset indent 45ctl_load="YES" 46.Ed 47.Sh DESCRIPTION 48The 49.Nm 50subsystem provides SCSI disk and processor emulation. 51It supports features such as: 52.Pp 53.Bl -bullet -compact 54.It 55Disk and processor device emulation 56.It 57Tagged queueing 58.It 59SCSI task attribute support (ordered, head of queue, simple tags) 60.It 61SCSI implicit command ordering support 62.It 63Full task management support (abort, LUN reset, target reset, etc.) 64.It 65Support for multiple ports 66.It 67Support for multiple simultaneous initiators 68.It 69Support for multiple simultaneous backing stores 70.It 71Support for VMWare VAAI: COMPARE AND WRITE, XCOPY, WRITE SAME, 72and UNMAP commands 73.It 74Support for Microsoft ODX: POPULATE TOKEN/WRITE USING TOKEN, 75WRITE SAME, and UNMAP commands 76.It 77Persistent reservation support 78.It 79Mode sense/select support 80.It 81Error injection support 82.It 83All I/O handled in-kernel, no userland context switch overhead 84.El 85.Pp 86It also serves as a kernel component of the native iSCSI target. 87.Sh SYSCTL VARIABLES 88The following variables are available as both 89.Xr sysctl 8 90variables and 91.Xr loader 8 92tunables: 93.Bl -tag -width indent 94.It Va kern.cam.ctl.debug 95Bit mask of enabled CTL log levels: 96.Bl -tag -offset indent -compact 97.It 1 98log commands with errors; 99.It 2 100log all commands; 101.It 4 102log received data for commands except READ/WRITE. 103.El 104Defaults to 0. 105.It Va kern.cam.ctl.iscsi.debug 106Verbosity level for log messages from the kernel part of iSCSI target. 107Set to 0 to disable logging or 1 to warn about potential problems. 108Larger values enable debugging output. 109Defaults to 1. 110.It Va kern.cam.ctl.iscsi.maxcmdsn_delta 111The number of outstanding commands to advertise to the iSCSI initiator. 112Technically, it is the difference between ExpCmdSN and MaxCmdSN fields 113in the iSCSI PDU. 114Defaults to 256. 115.It Va kern.cam.ctl.iscsi.ping_timeout 116The number of seconds to wait for the iSCSI initiator to respond to a NOP-In 117PDU. 118In the event that there is no response within that time the session gets 119forcibly terminated. 120Set to 0 to disable sending NOP-In PDUs. 121Defaults to 5. 122.El 123.Sh SEE ALSO 124.Xr ctladm 8 , 125.Xr ctld 8 , 126.Xr ctlstat 8 127.Sh HISTORY 128The 129.Nm 130subsystem first appeared in 131.Fx 9.1 . 132.Sh AUTHORS 133The 134.Nm 135subsystem was written by 136.An Kenneth Merry Aq Mt ken@FreeBSD.org . 137