Date: Sat, 11 Mar 2017 20:23:05 +0000 (UTC) From: Alexander Motin <mav@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r315087 - head/share/man/man4 Message-ID: <201703112023.v2BKN5JO040123@repo.freebsd.org>
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Author: mav Date: Sat Mar 11 20:23:05 2017 New Revision: 315087 URL: https://svnweb.freebsd.org/changeset/base/315087 Log: Improve ctl(4) description, including frontends and backends. MFC after: 2 weeks Modified: head/share/man/man4/ctl.4 Modified: head/share/man/man4/ctl.4 ============================================================================== --- head/share/man/man4/ctl.4 Sat Mar 11 19:59:31 2017 (r315086) +++ head/share/man/man4/ctl.4 Sat Mar 11 20:23:05 2017 (r315087) @@ -1,5 +1,5 @@ .\" Copyright (c) 2013 Edward Tomasz Napierala -.\" Copyright (c) 2015 Alexander Motin <mav@FreeBSD.org> +.\" Copyright (c) 2015-2017 Alexander Motin <mav@FreeBSD.org> .\" All rights reserved. .\" .\" Redistribution and use in source and binary forms, with or without @@ -24,15 +24,14 @@ .\" SUCH DAMAGE. .\" .\" $FreeBSD$ -.Dd January 19, 2017 +.Dd March 11, 2017 .Dt CTL 4 .Os .Sh NAME .Nm ctl -.Nd CAM Target Layer / iSCSI target +.Nd CAM Target Layer / SCSI target subsystem .Sh SYNOPSIS -To compile this driver into the kernel, -place the following line in your +To compile this driver into the kernel, place the following line in your kernel configuration file: .Bd -ragged -offset indent .Cd "device iscsi" @@ -48,45 +47,87 @@ ctl_load="YES" .Sh DESCRIPTION The .Nm -subsystem provides SCSI disk and processor emulation. +subsystem provides featured, performant and reliable SCSI target devices +emulation. It supports features such as: .Pp .Bl -bullet -compact .It Disk, processor and cdrom device emulation .It -Tagged queueing +Tagged and untagged queueing .It SCSI task attribute support (ordered, head of queue, simple tags) .It SCSI implicit command ordering support .It -Full task management support (abort, LUN reset, target reset, etc.) +Full task management support (abort, query, reset, etc.) .It -Support for multiple ports +Support for multiple ports, initiators, targets and backing stores .It -Support for multiple simultaneous initiators -.It -Support for multiple simultaneous backing stores -.It -Support for VMWare VAAI: COMPARE AND WRITE, XCOPY, WRITE SAME, -and UNMAP commands -.It -Support for Microsoft ODX: POPULATE TOKEN/WRITE USING TOKEN, -WRITE SAME, and UNMAP commands +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 -Mode sense/select support +Extensive VPD/mode/log pages support .It -Error injection support +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 -It also serves as a kernel component of the native iSCSI target. +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 on 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
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