231 lines
7.1 KiB
Groff
231 lines
7.1 KiB
Groff
.\" Copyright (c) 2013 Edward Tomasz Napierala
|
|
.\" Copyright (c) 2015-2017 Alexander Motin <mav@FreeBSD.org>
|
|
.\" 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 March 19, 2017
|
|
.Dt CTL 4
|
|
.Os
|
|
.Sh NAME
|
|
.Nm ctl
|
|
.Nd CAM Target Layer / iSCSI target subsystem
|
|
.Sh SYNOPSIS
|
|
To compile this driver into the kernel,
|
|
place the following line in your
|
|
kernel configuration file:
|
|
.Bd -ragged -offset indent
|
|
.Cd "device iscsi"
|
|
.Cd "device ctl"
|
|
.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
|
|
ctl_load="YES"
|
|
.Ed
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Nm
|
|
subsystem provides SCSI target devices emulation.
|
|
It supports features such as:
|
|
.Pp
|
|
.Bl -bullet -compact
|
|
.It
|
|
Disk, CD-ROM and processor device emulation
|
|
.It
|
|
Tagged queueing
|
|
.It
|
|
SCSI task attribute support (ordered, head of queue, simple tags)
|
|
.It
|
|
SCSI implicit command ordering support
|
|
.It
|
|
Full task management support (abort, query, reset, etc.)
|
|
.It
|
|
Support for multiple ports, initiators, targets and backing stores
|
|
.It
|
|
Support for VMWare VAAI and Microsoft ODX offload (COMPARE AND WRITE,
|
|
XCOPY, POPULATE TOKEN/WRITE USING TOKEN, WRITE SAME and UNMAP)
|
|
.It
|
|
Persistent reservation support
|
|
.It
|
|
Extensive VPD/mode/log pages support
|
|
.It
|
|
Featured error reporting, error injection and basic SMART support
|
|
.It
|
|
High Availability clustering support with ALUA
|
|
.It
|
|
All I/O handled in-kernel, no userland context switch overhead
|
|
.El
|
|
.Pp
|
|
The
|
|
.Nm
|
|
subsystem includes multiple frontends to provide access using different
|
|
transport protocols and implementations:
|
|
.Bl -tag -width cfumass
|
|
.It camsim
|
|
Provides access for local system via virtual initiator mode
|
|
.Xr CAM 4
|
|
SIM.
|
|
.It camtgt
|
|
Provides access for remote systems via target mode
|
|
.Xr CAM 4
|
|
SIMs, such as Fibre Channel
|
|
.Xr isp 4
|
|
and
|
|
.Xr mpt 4 .
|
|
.It cfumass
|
|
Provides access for remote systems via USB Mass Storage Class
|
|
Bulk Only (BBB) Transport.
|
|
.It ha
|
|
Internal frontend used to receive requests from other node ports in
|
|
High Availability cluster.
|
|
.It ioctl
|
|
Provides access for local user-level applications via
|
|
.Xr ioctl 2
|
|
based API.
|
|
.It iscsi
|
|
Combined with
|
|
.Xr iscsi 4
|
|
and
|
|
.Xr ctld 8 ,
|
|
provides access for remote systems via iSCSI protocol.
|
|
.It tpc
|
|
Internal frontend used to receive requests from Third Party Copy engine,
|
|
implementing copy offload operations.
|
|
.El
|
|
.Pp
|
|
The
|
|
.Nm
|
|
subsystem includes two backends to create logical units using different
|
|
kinds of backing stores:
|
|
.Bl -tag -width ramdisk
|
|
.It block
|
|
Stores data in ZFS ZVOLs, files or raw block devices.
|
|
.It ramdisk
|
|
Stores data in RAM, that makes it mostly useful for performance testing.
|
|
Depending on configured capacity can work as black hole, thin or thick
|
|
provisioned disk.
|
|
.El
|
|
.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.cam.ctl.debug
|
|
Bit mask of enabled CTL log levels:
|
|
.Bl -tag -offset indent -compact
|
|
.It 1
|
|
log commands with errors;
|
|
.It 2
|
|
log all commands;
|
|
.It 4
|
|
log data for commands other then READ/WRITE.
|
|
.El
|
|
Defaults to 0.
|
|
.It Va kern.cam.ctl.ha_id
|
|
Specifies unique position of this node within High Availability cluster.
|
|
Default is 0 -- no HA, 1 and 2 -- HA enabled at specified position.
|
|
.It Va kern.cam.ctl.ha_mode
|
|
Specifies High Availability cluster operation mode:
|
|
.Bl -tag -offset indent -compact
|
|
.It 0
|
|
Active/Standby -- primary node has backend access and processes requests,
|
|
while secondary can only do basic LUN discovery and reservation;
|
|
.It 1
|
|
Active/Active -- both nodes have backend access and process requests,
|
|
while secondary node synchronizes processing with primary one;
|
|
.It 2
|
|
Active/Active -- primary node has backend access and processes requests,
|
|
while secondary node forwards all requests and data to primary one;
|
|
.El
|
|
All above modes require established connection between HA cluster nodes.
|
|
If connection is not configured, secondary node will report Unavailable
|
|
state; if configured but not established -- Transitioning state.
|
|
Defaults to 0.
|
|
.It Va kern.cam.ctl.ha_peer
|
|
String value, specifying method to establish connection to peer HA node.
|
|
Can be "listen IP:port", "connect IP:port" or empty.
|
|
.It Va kern.cam.ctl.ha_link
|
|
Reports present state of connection between HA cluster nodes:
|
|
.Bl -tag -offset indent -compact
|
|
.It 0
|
|
not configured;
|
|
.It 1
|
|
configured but not established;
|
|
.It 2
|
|
established.
|
|
.El
|
|
.It Va kern.cam.ctl.ha_role
|
|
Specifies default role of this node:
|
|
.Bl -tag -offset indent -compact
|
|
.It 0
|
|
primary;
|
|
.It 1
|
|
secondary.
|
|
.El
|
|
This role can be overridden on per-LUN basis using "ha_role" LUN option,
|
|
so that for one LUN one node is primary, while for another -- another.
|
|
Role change from primary to secondary for HA modes 0 and 2 closes backends,
|
|
the opposite change -- opens.
|
|
If there is no primary node (both nodes are secondary, or secondary node has
|
|
no connection to primary one), secondary node(s) report Transitioning state.
|
|
State with two primary nodes is illegal (split brain condition).
|
|
.It Va kern.cam.ctl.iscsi.debug
|
|
Verbosity level for log messages from the kernel part of iSCSI target.
|
|
Set to 0 to disable logging or 1 to warn about potential problems.
|
|
Larger values enable debugging output.
|
|
Defaults to 1.
|
|
.It Va kern.cam.ctl.iscsi.maxtags
|
|
The number of outstanding commands to advertise to each iSCSI initiator.
|
|
Current implementation is not very accurate, so do not set this below 2.
|
|
Defaults to 256.
|
|
.It Va kern.cam.ctl.iscsi.ping_timeout
|
|
The number of seconds to wait for the iSCSI initiator to respond to a NOP-In
|
|
PDU.
|
|
In the event that there is no response within that time the session gets
|
|
forcibly terminated.
|
|
Set to 0 to disable sending NOP-In PDUs.
|
|
Defaults to 5.
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr cfumass 4 ,
|
|
.Xr ctladm 8 ,
|
|
.Xr ctld 8 ,
|
|
.Xr ctlstat 8
|
|
.Sh HISTORY
|
|
The
|
|
.Nm
|
|
subsystem first appeared in
|
|
.Fx 9.1 .
|
|
.Sh AUTHORS
|
|
The
|
|
.Nm
|
|
subsystem was originally written by
|
|
.An Kenneth Merry Aq Mt ken@FreeBSD.org .
|
|
Later work was done by
|
|
.An Alexander Motin Aq Mt mav@FreeBSD.org .
|