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20121028

The iSCSI target for Debian/NetBSD/FreeBSD

This software (istgt) is the implementation of iSCSI target
(refer to RFC3720 about iSCSI) for FreeBSD 7.1 or later.
It includes iSCSI protocol processor and SPC-3 (SCSI Primary
Commands - 3) based logical unit emulation.
You can easily create over 2TB storage for iSCSI target.
If necessary, you can configure to use multipath failover or
MCS failover.

If you want use the command queuing, change QueueDepth key of
the configuration. Because default is comment out, you only
remove # from this line to make the parameter take effect.
The command queuing is not yet stable. If you have any problem,
comment out or specify 0 to disable it. The small QueueDepth
may cause a problem. I recommend you to specify more than 32.

You can use a file or any raw device as the backing store.
Microsoft Windows Server 2008 or Microsoft iSCSI initiator 2.08
or later is recommended.
Diskless iSCSI boot is tested with Intel PRO/1000 PT Server
Adapter and Windows Server 2003/2008/2008R2/Windows7 RC.
iSCSI install/boot is tested with gPXE 1.0.0 and WS2K8/2K8R2/W7.
Intel Gigabit CT Desktop Adapter is tested with WS 2K8R2/W7.

This software is under development and less document.
The format of the configuration file may frequently be changed.
Please use it carefully.
It is made based on the concept of my own MCS extra patch
(release 20090125) for iscsi-target (netbsd-iscsi-20080207).

If you want to run FreeBSD in Hyper-V environment,
please use my small kernel patch of reboot issue which can be
downloaded below.

The latest version is available at:
http://shell.peach.ne.jp/aoyama/

For FreeBSD initiator, please check here:
ftp://ftp.cs.huji.ac.il/users/danny/freebsd/

Using path-through tape drive from Microsoft iSCSI Initiator:
open registry of initiator by regedit.exe.
change the value of MaxTransferLength to 0x10000 (65536).
reboot Windows.
(0000 is an instance number. It might be a different value.)

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\
{4D36E97B-E325-11CE-BFC1-08002BE10318}\0000\Parameters\
MaxTransferLength

Timeout of Microsoft iSCSI Initiator:
If you want fast recovery from failure, try to decrease the value in
above registry:
LinkDownTime
TCPConnectTime
TCPDisconnectTime
DelayBetweenReconnect

If you want to keep failed command, try to increase:
MaxRequestHoldTime
SrbTimeoutDelta


External Libs:
 o OpenSSL (shipped with FreeBSD)
 o CAM (shipped with FreeBSD)
 o VirtualBox 4.x DSO (if use --with-vbox configure option)

Tested Initiators:
 o Microsoft Windows Server 2008 (builtin)
 o Microsoft Windows Server 2008 R2 (builtin)
 o Microsoft Windows 7 Ultimate x64 (builtin)
 o Microsoft Windows 8 Preview x64 (builtin)
 o Microsoft iSCSI Initiator 2.08 on WS2003
 o Intel iSCSI Remote Boot 2.1.22
 o Intel iSCSI Remote Boot 2.3.81
 o Intel iSCSI Remote Boot 2.5.12 (CT Desktop Adapter)
 o Intel iSCSI Remote Boot 2.7.44 (ET Dual Port Server Adapter)
 o Sun VirtualBOX 2.1.2 (builtin)
 o Sun VirtualBOX 3.0.12 (builtin)
 o Sun VirtualBOX 3.1.2 (builtin)
 o VMware ESXi 3.5 Update 3 (builtin)
 o VMware ESXi 4.0 (builtin)
 o VMware ESXi 4.1 Update 1 (builtin)
 o VMware ESXi 5.0 (builtin)
 o VMware ESXi 5.1 (builtin)
 o Xen Server 5.0 Update 3 (builtin)
 o Xen Server 5.5 (builtin)
 o FreeBSD 7.1 + iscsi 2.1.3
 o FreeBSD 7.2 + iscsi 2.2.3
 o FreeBSD 7.3 + iscsi 2.2.4
 o FreeBSD 8.2 + isboot 0.2.3
 o FreeBSD 9.1 + isboot 0.2.6
 o CentOS 5.2 + Open-iSCSI (package)
 o Ubuntu 9.10 + Open-iSCSI (package)
 o gPXE 1.0.0 + VirtualBox 3.1.2 on FreeNAS 0.7.1
 o iPXE 1.0.0 + isboot 0.2.5 + FreeBSD 9.1
 o FreeNAS 0.7.1 (FreeBSD 7.2/7.3 + iscsi 2.2.4)
 o FreeNAS 0.7.2 (FreeBSD 7.3 + iscsi 2.2.4)
 o FreeNAS 0.7.5 (FreeBSD 9.0 + iscsi 2.3.1.0)
 o NAS4Free 9.1.0.1 (FreeBSD 9.1 + iscsi 2.3.1.0)

Features:
 o MCS/MPIO for failover (up to 255 concurrent sessions)
 o Multipath I/O (only support Microsoft MPIO/VMware ESXi)
 o SPC-3 Persistent Reservation for cluster nodes
 o 64bit LBA for over 2TB
 o Header/Data digest by CRC32C
 o CHAP w/Mutual authentication
 o Multiple LUNs and ACLs for portals
 o IPv6/IPv4 dual support
 (experimental features)
 o Command Queuing (up to 255 depth, 32 by default)
 o iSCSI boot with Intel PRO/1000 Server Adapters
 o virtual DVD-ROM and virtual tape drive (DLT emulator)
 o pass-through device (only support DA/SA/CD/CH type)

Current Limitations:
 o can't create empty VirtualBox VirtualDisk.
 o The parameters other than PG, IG, and LU are not reloaded by SIGHUP.
 o PG and IG mapped to LU can't be deleted by SIGHUP.
 o LU connected by the initiator can't be reloaded by SIGHUP.
 o If you delete an active LU, all connections of the LU are closed by SIGHUP.
 o Updating IG is not affected until the next login.
 o logical unit is sharing with exclusive lock
 o exclusive port w/asynchronous operation
 o command queuing is incomplete for multiple initiators
 o LUN1 and more are shared information of LUN0 (e.g. UnitInquiry)
 o APTPL (Activate Persist Through Power Loss) is not supported
 o TPGS is incomplete for multipath failover (disabled by default)
 o path-through SA variable length must not exceed 65536 (CAM limit)
 o maximum LUN is 63
 o maximum PortalGroup are 1024
 o maximum InitiatorGroup, LogicalUnit are 4096
 o maximum mapping per target is 256
 o maximum concurrent session identifier per target is 255
 o maximum persistent reservation keys per target is 256
 (most case of limitation is due to memory allocation and finding
  method by linear search)

Special Thanks to:
Isao Takatani (bug report and idea suggestion)
Toshiya Shimpo of Meikohsha Information System Co.,Ltd
Yoshio Takii of Meikohsha Information System Co.,Ltd

Author:
Daisuke Aoyama <aoyama@peach.ne.jp>