LIO

The Linux SCSI Target Wiki

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{{Infobox software
{{Infobox software
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| name                  = {{Target}}
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| name                  = {{Target|1}}
| logo                  = [[Image:Corp_Logo.png|180px|Logo]]
| logo                  = [[Image:Corp_Logo.png|180px|Logo]]
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| screenshot            = {{RTS screenshot|{{Target}}}}
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| screenshot            = {{RTS screenshot|{{Target|1}}}}
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| caption                = {{Target}}
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| caption                = {{Target|1}}
| collapsible            =  
| collapsible            =  
| author                = {{Nicholas Bellinger}}
| author                = {{Nicholas Bellinger}}
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{{Image|Linux-fireware-target-bootc-macosx.png|The IEEE Firewire driver exporting IBLOCK LUNs to a MacOS-X based IEEE-1394/FireWire client.}}
{{Image|Linux-fireware-target-bootc-macosx.png|The IEEE Firewire driver exporting IBLOCK LUNs to a MacOS-X based IEEE-1394/FireWire client.}}
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The '''{{Target}}''' has defined the Linux block storage standard since kernel version {{RTS releases|LIO|kernel_ver}}.<ref name=h-online>{{cite web| url=http://www.h-online.com/open/features/Kernel-Log-Coming-in-2-6-38-Part-4-Storage-1199926.html| title=Kernel Log: Coming in 2.6.38 (Part 4) - Storage| author=Thorsten Leemhuis| publisher=Heise Online| date=2011-03-02}}</ref><ref name=lwn>{{cite web| url=http://lwn.net/SubscriberLink/420691/eb6ae8a12222aac6/| title=Shooting at SCSI targets| author=Jonathan Corbet| date=2010-12-22| publisher=lnw.net}}</ref> It supports a rapidly growing number of [[#Fabric modules|fabric modules]], and all existing Linux block devices as [[#Backstores|backstores]].
+
The '''{{Target|1}}''' has defined the Linux block storage standard since kernel version {{RTS releases|LIO|kernel_ver}}.<ref name=h-online>{{cite web| url=http://www.h-online.com/open/features/Kernel-Log-Coming-in-2-6-38-Part-4-Storage-1199926.html| title=Kernel Log: Coming in 2.6.38 (Part 4) - Storage| author=Thorsten Leemhuis| publisher=Heise Online| date=2011-03-02}}</ref><ref name=lwn>{{cite web| url=http://lwn.net/SubscriberLink/420691/eb6ae8a12222aac6/| title=Shooting at SCSI targets| author=Jonathan Corbet| date=2010-12-22| publisher=lnw.net}}</ref> It supports a rapidly growing number of [[#Fabric modules|fabric modules]], and all existing Linux block devices as [[#Backstores|backstores]].
== Overview ==
== Overview ==
-
The {{Target}} is based on a SCSI engine that implements the semantics of a SCSI target as described in the SCSI Architecture Model (SAM), and supports its comprehensive [[SPC-3]]/[[SPC-4]] feature set in a fabric-agnostic way. The SCSI target core does not directly communicate with initiators and it does not directly access data on disk.
+
{{Target}} is based on a SCSI engine that implements the semantics of a SCSI target as described in the SCSI Architecture Model (SAM), and supports its comprehensive [[SPC-3]]/[[SPC-4]] feature set in a fabric-agnostic way. The SCSI target core does not directly communicate with initiators and it does not directly access data on disk.
{{LIO}} has obtained [[VMware vSphere]]&nbsp;4 Ready certification on Buffalo [[http://www.risingtidesystems.com/doc/VMware_HCL_Buffalo.pdf PDF]] and QNAP [[http://www.risingtidesystems.com/doc/VMware_HCL_QNAP.pdf PDF]] systems, and vSphere&nbsp;5 Ready certification on Netgear [[http://www.risingtidesystems.com/doc/VMware_HCL_Netgear.pdf PDF]] and Pure Storage [[http://www.risingtidesystems.com/doc/VMware_HCL_PureStorage.pdf PDF]] systems.
{{LIO}} has obtained [[VMware vSphere]]&nbsp;4 Ready certification on Buffalo [[http://www.risingtidesystems.com/doc/VMware_HCL_Buffalo.pdf PDF]] and QNAP [[http://www.risingtidesystems.com/doc/VMware_HCL_QNAP.pdf PDF]] systems, and vSphere&nbsp;5 Ready certification on Netgear [[http://www.risingtidesystems.com/doc/VMware_HCL_Netgear.pdf PDF]] and Pure Storage [[http://www.risingtidesystems.com/doc/VMware_HCL_PureStorage.pdf PDF]] systems.
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== Setup ==
== Setup ==
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''[[targetcli]]'' provides a comprehensive, powerful and easy CLI tool to configure and manage {{Target}}s. ''targetcli'' was developed by {{RTS full}}.
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''[[targetcli]]'' provides a comprehensive, powerful and easy CLI tool to configure and manage {{Target}}. ''targetcli'' was developed by {{RTS full}}.
== {{anchor|Fabric modules}}Fabric modules ==
== {{anchor|Fabric modules}}Fabric modules ==
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== {{anchor|Backstores}} Backstores ==
== {{anchor|Backstores}} Backstores ==
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Backstores implement the "backend" of the {{Target}}. They implement the methods of accessing data on disk. A backstore subsystem plugin is a physical storage object that provides the block device underlying a SCSI [[#Endpoint|Endpoint]].
+
Backstores implement the {{Target}} "backend". They implement the methods of accessing data on disk. A backstore subsystem plugin is a physical storage object that provides the block device underlying a SCSI [[#Endpoint|Endpoint]].
-
Backstore objects can be added via the ''Storage Hardware Abstraction Layer'' (''S-HAL'') that brings storage hardware into the {{Target}} engine as raw block devices, on which the Linux stack just works (including complex functionality such as software RAID, LVM, snapshots, virtualization, etc.).
+
Backstore objects can be added via the ''Storage Hardware Abstraction Layer'' (''S-HAL'') that brings storage hardware into {{Target}} engine as raw block devices, on which the Linux stack just works (including complex functionality such as software RAID, LVM, snapshots, virtualization, etc.).
-
The {{Target}} supports the [[SCSI-3]] standard for all backstore devices (block devices and/or VFS):
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{{Target}} supports the [[SCSI-3]] standard for all backstore devices (block devices and/or VFS):
* {{anchor|FILEIO}} '''FILEIO''' (Linux VFS devices): any file on a mounted filesystem. It may be backed by a file or an underlying real block device. FILEIO is using struct file to serve block I/O with various methods (synchronous or asynchronous) and (buffered or direct). The Linux kernel code for filesystems resides in ''linux/fs''. By default, [[FILEIO]] uses <code>O_SYNC</code>.
* {{anchor|FILEIO}} '''FILEIO''' (Linux VFS devices): any file on a mounted filesystem. It may be backed by a file or an underlying real block device. FILEIO is using struct file to serve block I/O with various methods (synchronous or asynchronous) and (buffered or direct). The Linux kernel code for filesystems resides in ''linux/fs''. By default, [[FILEIO]] uses <code>O_SYNC</code>.
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* {{anchor|RAMDISK|RAMDISK_MCP|RD_MCP}} '''Memory Copy RAMDISK''' (Linux RAMDISK_MCP): Memory Copy ram disks (''rd_mcp'') provide ram disks with full SCSI emulation and separate memory mappings using memory copy for initiators, thus providing multi-session capability. This is most useful for fast volatile mass storage for production.
* {{anchor|RAMDISK|RAMDISK_MCP|RD_MCP}} '''Memory Copy RAMDISK''' (Linux RAMDISK_MCP): Memory Copy ram disks (''rd_mcp'') provide ram disks with full SCSI emulation and separate memory mappings using memory copy for initiators, thus providing multi-session capability. This is most useful for fast volatile mass storage for production.
-
The SCSI functionality is implemented directly in the target engine in a fabric-agnostic way, including a number of high-end features, such as [[Persistent Reservations]] (PRs) and [[Asymmetric Logical Unit Assignment]] (ALUA), following the [[SPC-4]] standard.
+
The SCSI functionality is implemented directly in the {{Target|1}} engine in a fabric-agnostic way, including a number of high-end features, such as [[Persistent Reservations]] (PRs) and [[Asymmetric Logical Unit Assignment]] (ALUA), following the [[SPC-4]] standard.
The backstore devices ([[FILEIO]], [[IBLOCK]], [[pSCSI]], [[RAMDISK]], etc.) report the underlying HW limitiations for things like TCQ depth, ''MaxSectors'', ''TaskAbortedStatus'', ''UA Interlocking'', etc. All of these values are available as attributes in the ''[[targetcli]]'' device context.
The backstore devices ([[FILEIO]], [[IBLOCK]], [[pSCSI]], [[RAMDISK]], etc.) report the underlying HW limitiations for things like TCQ depth, ''MaxSectors'', ''TaskAbortedStatus'', ''UA Interlocking'', etc. All of these values are available as attributes in the ''[[targetcli]]'' device context.
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* {{anchor|Demo Mode}} '''Demo Mode''': Means disabling authentification for an iSCSI Endpoint, i.e. its [[ACL]]s are diabled. Demo Mode grants read-only access to all iSCSI Initiators that attempt to connect to that specific Endpoint. See the [[iSCSI]] entry on how to enable [[iSCSI#Demo mode|Demo Mode]].
* {{anchor|Demo Mode}} '''Demo Mode''': Means disabling authentification for an iSCSI Endpoint, i.e. its [[ACL]]s are diabled. Demo Mode grants read-only access to all iSCSI Initiators that attempt to connect to that specific Endpoint. See the [[iSCSI]] entry on how to enable [[iSCSI#Demo mode|Demo Mode]].
* {{anchor|EUI}} '''Extended Unique Identifier''' ('''EUI'''): A 64-bit number that uniquely identifies every device in the world. The format consists of 24 bits that are unique to a given company, and 40 bits assigned by the company to each device it builds.
* {{anchor|EUI}} '''Extended Unique Identifier''' ('''EUI'''): A 64-bit number that uniquely identifies every device in the world. The format consists of 24 bits that are unique to a given company, and 40 bits assigned by the company to each device it builds.
-
* {{anchor|I_T Nexus}} '''I_T Nexus''': An I_T Nexus denotes a live session between an [[Initiator]] and a Target.
+
* {{anchor|I_T Nexus}} '''I_T Nexus''': An I_T Nexus denotes a live session between an [[Initiator]] and a target.
* {{anchor|Initiator}} '''[[Initiator]]''': The originating end of a SCSI session. Typically a controlling device such as a computer.
* {{anchor|Initiator}} '''[[Initiator]]''': The originating end of a SCSI session. Typically a controlling device such as a computer.
* {{anchor|IPS}} '''Internet Protocol Storage''' ('''IPS'''): The class of protocols or devices that use the IP protocol to move data in a storage network. FCIP, iFCP, and [[iSCSI]] are all examples of IPS protocols.
* {{anchor|IPS}} '''Internet Protocol Storage''' ('''IPS'''): The class of protocols or devices that use the IP protocol to move data in a storage network. FCIP, iFCP, and [[iSCSI]] are all examples of IPS protocols.
* {{anchor|IQN}} '''iSCSI Qualified Name''' ('''IQN'''): A name format for iSCSI that uniquely identifies every device in the world (e.g. iqn.5886.com.acme.tapedrive.sn-a12345678).
* {{anchor|IQN}} '''iSCSI Qualified Name''' ('''IQN'''): A name format for iSCSI that uniquely identifies every device in the world (e.g. iqn.5886.com.acme.tapedrive.sn-a12345678).
-
* {{anchor|ISID}} '''Initiator Session Identifier''' ('''ISID'''): A 48-bit number, generated by the Initiator, that uniquely identifies a session between the Initiator and the Target. This value is created during the login process, and is sent to the Target with a Login PDU.
+
* {{anchor|ISID}} '''Initiator Session Identifier''' ('''ISID'''): A 48-bit number, generated by the Initiator, that uniquely identifies a session between the Initiator and the target. This value is created during the login process, and is sent to the target with a Login PDU.
* {{anchor|MPIO}} '''Multipath I/O''' ('''MPIO'''): A method by which data can take multiple redundant paths between a server and storage.
* {{anchor|MPIO}} '''Multipath I/O''' ('''MPIO'''): A method by which data can take multiple redundant paths between a server and storage.
* {{anchor|Network Portal}} '''Network Portal''': The combination of an iSCSI Endpoint with an IP address plus a TCP port. The TCP port number for the iSCSI protocol defined by IANA is 3260.
* {{anchor|Network Portal}} '''Network Portal''': The combination of an iSCSI Endpoint with an IP address plus a TCP port. The TCP port number for the iSCSI protocol defined by IANA is 3260.
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== Inclusion in Linux distributions ==
== Inclusion in Linux distributions ==
-
The {{Target}} and ''[[targetcli]]'' are included in most Linux distributions per default. Here is an overview over the most popular distributions:
+
{{Target}} and ''[[targetcli]]'' are included in most Linux distributions per default. Here is an overview over the most popular distributions:
{{Linux Inclusion}}
{{Linux Inclusion}}
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== Timeline ==
== Timeline ==
-
The {{Target}} and fabric modules have gone upstream into the Linux kernel as follows:
+
{{Target}} and fabric modules have gone upstream into the Linux kernel as follows:
-
* Linux 2.6.38 (2011-03-14<ref>{{cite web| url=https://lkml.org/lkml/2011/3/14/508| title=Linux 2.6.38| author=Linus Torvalds| date=2011-03-14| publisher=lkml.org}}</ref>): {{Target}} engine<ref>{{cite web| url=http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=38567333a6dabd0f2b4150e9fb6dd8e3ba2985e5| title=Target merge| author=Linus Torvalds| date=2011-01-14| publisher=lkml.org}}</ref>
+
* Linux 2.6.38 (2011-03-14<ref>{{cite web| url=https://lkml.org/lkml/2011/3/14/508| title=Linux 2.6.38| author=Linus Torvalds| date=2011-03-14| publisher=lkml.org}}</ref>): {{Target|1}} engine<ref>{{cite web| url=http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=38567333a6dabd0f2b4150e9fb6dd8e3ba2985e5| title=Target merge| author=Linus Torvalds| date=2011-01-14| publisher=lkml.org}}</ref>
* Linux 2.6.39 (2011-05-18<ref>{{cite web| url=https://lkml.org/lkml/2011/5/19/16| title=Linux 2.6.39| author=Linus Torvalds| date=2011-05-18| publisher=lkml.org}}</ref>): [[tcm_loop]] (SCSI support on top of any raw hardware)
* Linux 2.6.39 (2011-05-18<ref>{{cite web| url=https://lkml.org/lkml/2011/5/19/16| title=Linux 2.6.39| author=Linus Torvalds| date=2011-05-18| publisher=lkml.org}}</ref>): [[tcm_loop]] (SCSI support on top of any raw hardware)
* Linux 3.0 (2011-07-21<ref>{{cite web| url=https://lkml.org/lkml/2011/7/21/455| title=Linux 3.0| author=Linus Torvalds| date=2011-07-21| publisher=lkml.org}}</ref>): [[Fibre Channel over Ethernet|FCoE]] (by Cisco)
* Linux 3.0 (2011-07-21<ref>{{cite web| url=https://lkml.org/lkml/2011/7/21/455| title=Linux 3.0| author=Linus Torvalds| date=2011-07-21| publisher=lkml.org}}</ref>): [[Fibre Channel over Ethernet|FCoE]] (by Cisco)

Revision as of 06:02, 29 September 2013

LIO
Logo
LIO 150513.png
LIO
Original author(s) Nicholas Bellinger
Developer(s) Datera, Inc.
Initial release January 14, 2011 (2011-01-14)
Stable release 4.1.0 / June 20, 2012;
7 years ago
 (2012-06-20)
Preview release 4.2.0-rc5 / June 28, 2012;
7 years ago
 (2012-06-28)
Development status Production
Written in C
Operating system Linux
Type SCSI target
License GNU General Public License
Website datera.io
architecture overview.
LinuxIO iSCSI architecture diagram.
SCSI Portal Group and multipath architecture overview.
SCSI standards diagram.
QLogic Fibre Channel running at line rate in target mode with PCIe device passthrough and MSI-X polled interrupts across Linux/SCSI qla2xxx LLD request and response rings.
The IEEE Firewire driver exporting IBLOCK LUNs to a MacOS-X based IEEE-1394/FireWire client.

The LIO has defined the Linux block storage standard since kernel version 2.6.38.[1][2] It supports a rapidly growing number of fabric modules, and all existing Linux block devices as backstores.

Contents

Overview

LinuxIO is based on a SCSI engine that implements the semantics of a SCSI target as described in the SCSI Architecture Model (SAM), and supports its comprehensive SPC-3/SPC-4 feature set in a fabric-agnostic way. The SCSI target core does not directly communicate with initiators and it does not directly access data on disk.

Template:LIO has obtained VMware vSphere 4 Ready certification on Buffalo [PDF] and QNAP [PDF] systems, and vSphere 5 Ready certification on Netgear [PDF] and Pure Storage [PDF] systems.

Native support in OpenStack (setup, code), starting with the Grizzly release, makes Template:LIO also an attractive storage option for cloud deployments.

The LinuxIO core (target_core.ko, see Linux kernel driver database) was released with the Linux kernel 2.6.38 on January 14, 2011 (2011-01-14).[3]

Setup

targetcli provides a comprehensive, powerful and easy CLI tool to configure and manage LinuxIO. targetcli was developed by Datera, Inc..

Fabric modules

Fabric modules implement the "frontend" of the SCSI target. They "speak" specific protocols that transport SCSI commands. The Fabric Hardware Abstraction Layer (F-HAL) allows all protocol-specific processing to be encapsulated in fabric modules. The following fabric modules are available:

Backstores

Backstores implement the LinuxIO "backend". They implement the methods of accessing data on disk. A backstore subsystem plugin is a physical storage object that provides the block device underlying a SCSI Endpoint.

Backstore objects can be added via the Storage Hardware Abstraction Layer (S-HAL) that brings storage hardware into LinuxIO engine as raw block devices, on which the Linux stack just works (including complex functionality such as software RAID, LVM, snapshots, virtualization, etc.).

LinuxIO supports the SCSI-3 standard for all backstore devices (block devices and/or VFS):

The SCSI functionality is implemented directly in the LIO engine in a fabric-agnostic way, including a number of high-end features, such as Persistent Reservations (PRs) and Asymmetric Logical Unit Assignment (ALUA), following the SPC-4 standard.

The backstore devices (FILEIO, IBLOCK, pSCSI, RAMDISK, etc.) report the underlying HW limitiations for things like TCQ depth, MaxSectors, TaskAbortedStatus, UA Interlocking, etc. All of these values are available as attributes in the targetcli device context.

Specifications

The following specifications are available as T10 Working Drafts:

Glossary

Inclusion in Linux distributions

LinuxIO and targetcli are included in most Linux distributions per default. Here is an overview over the most popular distributions:

Distribution Version[Linux 1] Release Archive Install Source git[Linux 2] Documentation
CentOS 6.2 2011-12-20 CentOS mirror su -c 'yum install fcoe-target-utils' targetcli-fb.git Tech Notes
Debian 7.0 ("wheezy") TBA Debian pool su -c 'apt-get install targetcli' targetcli
Fedora 16, 17/18 2011-11-08 Fedora Rawhide su -c 'yum install targetcli' targetcli-fb.git Target Wiki
openSUSE 12.1 2011-11-08 Requires manual installation from targetcli.
RHEL 6.2 2011-11-16 Fedora Rawhide su -c 'yum install fcoe-target-utils' targetcli-fb.git Tech Notes
Scientific Linux 6.2 2012-02-16 SL Mirror su -c 'yum install fcoe-target-utils' targetcli-fb.git Tech Notes
SLES SP2 2012-02-15 Requires manual installation from targetcli.
Ubuntu PrecisePangolin v12 2012-04-26 Ubuntu universe su -c 'apt-get install targetcli' targetcli
  1. The distribution release where LIO was included first.
  2. Technical support, and qualified backports to other kernels and distributions are available from Datera.

Timeline

LinuxIO and fabric modules have gone upstream into the Linux kernel as follows:

Wikipedia

Contact

Please direct all technical discussion on targetcli to the target-devel mailing list (post, subscribe, list info, gmane archive).

If you need assistance, or if you have an SLA with Datera, Inc., please contact the company at:

Please see Support for more information.

See also

Notes

  1. Thorsten Leemhuis (2011-03-02). "Kernel Log: Coming in 2.6.38 (Part 4) - Storage". Heise Online. 
  2. Jonathan Corbet (2010-12-22). "Shooting at SCSI targets". lnw.net. 
  3. Linus Torvalds (2011-03-14). "Linux 2.6.38". lkml.org. 
  4. Mark J. Sullivan (January 2010). Intel® Xeon® Processor C5500/C3500 Series Non-Transparent Bridge. 323328-001. Santa Clara: Intel. 
  5. Linus Torvalds (2011-03-14). "Linux 2.6.38". lkml.org. 
  6. Linus Torvalds (2011-01-14). "Target merge". lkml.org. 
  7. Linus Torvalds (2011-05-18). "Linux 2.6.39". lkml.org. 
  8. Linus Torvalds (2011-07-21). "Linux 3.0". lkml.org. 
  9. Linus Torvalds (2011-10-24). "Linux 3.1". lkml.org. 
  10. Linus Torvalds (2011-07-27). "iSCSI merge". lkml.org. 
  11. Linus Torvalds (2012-03-18). "Linux 3.3 release". lkml.org. 
  12. Linus Torvalds (2012-01-18). "InfiniBand/SRP merge". lkml.org. 
  13. Linus Torvalds (2012-07-21). "Linux 3.5 released". marc.info. 
  14. Linus Torvalds (2012-05-31). "scsi-misc". lkml.org. 
  15. Linus Torvalds (2012-05-22). "usb-target-merge". lkml.org. 
  16. Linus Torvalds (2012-05-23). "sbp-target-merge". lkml.org. 
  17. Linus Torvalds (2012-10-01). "Linux 3.6". lkml.org. 
  18. Linus Torvalds (2012-08-13). "tcm_vhost: Initial merge for vhost level target fabric driver". lkml.org. 
  19. Linus Torvalds (2013-04-28). "Linux 3.9 released". lkml.org. 
  20. Linus Torvalds (2013-06-30). "Linux 3.10". marc.org. 

External links

Timeline of the LinuxIO
Release Details 2011 2012 2013 2014 2015
123456789101112 123456789101112 123456789101112 123456789101112 123456789101112
4.x Version 4.0 4.1
Feature LIO Core Loop back FCoE iSCSI Perf SRP
CM WQ FC
USB
1394
vHost Perf Misc 16 GFC iSER Misc VAAI Misc DIF Core
NPIV
DIF iSER DIF FC vhost TCMU Xen Misc Misc virtio 1.0 Misc NVMe OF
Linux 2.6.38 2.6.39 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19 3.20 3.21 3.22
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