LIO Target
Encyclopedia
LIO Target is a multiprotocol SCSI
target for Linux
. It currently supports fabric modules for iSCSI
, Fibre Channel
, FCoE
and InfiniBand
(SRP
). LIO went upstream into Linux with kernel version 2.6.38, and is becoming the standard unified block storage target in Linux. Supported CPU architectures include x86, ia64, ARM, CELL, MIPS and POWER, etc.
target engine implements a comprehensive SPC-3/SPC-4 feature set with support for high-end SCSI features in a fabric-agnostic way, such as Persistent Reservations (PR) and Asymmetric Logical Unit Assignment (ALUA). The LIO iSCSI
fabric module also implements a number of advanced features, such as Multiple Connections per Session (MC/S) and Error Recovery Level 2 (ERL=2).
LIO has a configfs
-based kernel API, and can be managed via a comprehensive command-line interface and API (RTSadmin). RTSadmin version 2 allows unified management of all LIO block storage protocols, such as iSCSI
, Fibre Channel
, FCoE
and InfiniBand
. RTSadmin v2 is dual licensed, and the community edition is available under the AGPL.
LIO is being used in a number of commercial storage systems, including Netgear
, QNAP
, Synology
, etc.
Together with the replication software DRBD
and the cluster software Pacemaker, LIO allows the configuration of highly-available storage systems. RTSadmin, the management platform for LIO, supports easy setup and configuration of such HA arrays.
LIO is being developed by RisingTide Systems, located in the Silicon Valley, which manufactures storage systems and software. RisingTide Systems is a member of the Linux Solutions Group
(Lisog), where LIO provides the blocklevel storage component for the open source
reference stack.
target core is independent of specific fabric modules or backstore types. This way, LIO can support any number of fabrics and backstores, and allows using them together at the same time. The LIO modules have gone upstream or are scheduled to go upstream into the Linux kernel as follows:
iSCSI
initiator, called Core-iSCSI. Core-iSCSI supports a number of advanced iSCSI features, including, in particular, Multiple Connections per Session (MC/S) and Error Recovery Level 2 (ERL=2), which the standard Linux Open-iSCSI initiator doesn't support. This way, Core-iSCSI can drive increased availability, scalability and performance. Core-iSCSI also allows remote boot across an iSCSI
SAN or WAN ("diskless boot").
SCSI
Small Computer System Interface is a set of standards for physically connecting and transferring data between computers and peripheral devices. The SCSI standards define commands, protocols, and electrical and optical interfaces. SCSI is most commonly used for hard disks and tape drives, but it...
target for Linux
Linux
Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...
. It currently supports fabric modules for iSCSI
ISCSI
In computing, iSCSI , is an abbreviation of Internet Small Computer System Interface, an Internet Protocol -based storage networking standard for linking data storage facilities. By carrying SCSI commands over IP networks, iSCSI is used to facilitate data transfers over intranets and to manage...
, Fibre Channel
Fibre Channel
Fibre Channel, or FC, is a gigabit-speed network technology primarily used for storage networking. Fibre Channel is standardized in the T11 Technical Committee of the InterNational Committee for Information Technology Standards , an American National Standards Institute –accredited standards...
, FCoE
Fibre Channel over Ethernet
Fibre Channel over Ethernet is an encapsulation of Fibre Channel frames over Ethernet networks. This allows Fibre Channel to use 10 Gigabit Ethernet networks while preserving the Fibre Channel protocol...
and InfiniBand
InfiniBand
InfiniBand is a switched fabric communications link used in high-performance computing and enterprise data centers. Its features include high throughput, low latency, quality of service and failover, and it is designed to be scalable...
(SRP
SCSI RDMA Protocol
In computing the SCSI RDMA Protocol is a protocol that allows one computer to access SCSI devices attached to another computer via remote direct memory access . The SRP protocol is also known as the SCSI Remote Protocol. The use of RDMA makes higher throughput and lower latency possible than what...
). LIO went upstream into Linux with kernel version 2.6.38, and is becoming the standard unified block storage target in Linux. Supported CPU architectures include x86, ia64, ARM, CELL, MIPS and POWER, etc.
Features
The LIO SCSISCSI
Small Computer System Interface is a set of standards for physically connecting and transferring data between computers and peripheral devices. The SCSI standards define commands, protocols, and electrical and optical interfaces. SCSI is most commonly used for hard disks and tape drives, but it...
target engine implements a comprehensive SPC-3/SPC-4 feature set with support for high-end SCSI features in a fabric-agnostic way, such as Persistent Reservations (PR) and Asymmetric Logical Unit Assignment (ALUA). The LIO iSCSI
ISCSI
In computing, iSCSI , is an abbreviation of Internet Small Computer System Interface, an Internet Protocol -based storage networking standard for linking data storage facilities. By carrying SCSI commands over IP networks, iSCSI is used to facilitate data transfers over intranets and to manage...
fabric module also implements a number of advanced features, such as Multiple Connections per Session (MC/S) and Error Recovery Level 2 (ERL=2).
LIO has a configfs
Configfs
Configfs is a RAM-based virtual file system provided by the 2.6 Linux kernel. Configfs appears similar to sysfs but they are in fact different and complementary. Configfs is for creating, managing and destroying kernel objects from user-space, and sysfs for viewing and manipulating objects from...
-based kernel API, and can be managed via a comprehensive command-line interface and API (RTSadmin). RTSadmin version 2 allows unified management of all LIO block storage protocols, such as iSCSI
ISCSI
In computing, iSCSI , is an abbreviation of Internet Small Computer System Interface, an Internet Protocol -based storage networking standard for linking data storage facilities. By carrying SCSI commands over IP networks, iSCSI is used to facilitate data transfers over intranets and to manage...
, Fibre Channel
Fibre Channel
Fibre Channel, or FC, is a gigabit-speed network technology primarily used for storage networking. Fibre Channel is standardized in the T11 Technical Committee of the InterNational Committee for Information Technology Standards , an American National Standards Institute –accredited standards...
, FCoE
Fibre Channel over Ethernet
Fibre Channel over Ethernet is an encapsulation of Fibre Channel frames over Ethernet networks. This allows Fibre Channel to use 10 Gigabit Ethernet networks while preserving the Fibre Channel protocol...
and InfiniBand
InfiniBand
InfiniBand is a switched fabric communications link used in high-performance computing and enterprise data centers. Its features include high throughput, low latency, quality of service and failover, and it is designed to be scalable...
. RTSadmin v2 is dual licensed, and the community edition is available under the AGPL.
LIO is being used in a number of commercial storage systems, including Netgear
Netgear
Netgear is a U.S. manufacturer of computer networking equipment and other computer hardware....
, QNAP
QNAP TS-101
The TS-101 is a network-attached storage appliance with built-in functionality from QNAP Systems Inc. . The system is the size of a USB harddrive with a fanless housing.-Main Features:Out of the box, the TS-101 has the following features:...
, Synology
Synology
For information of Sinology, Chinese Studies, see here.Synology Inc , founded in April 2000, is a Taiwanese company that produces network attached storage appliances for the SOHO and SMB/SME...
, etc.
Together with the replication software DRBD
DRBD
DRBD is a distributed storage system for the GNU/Linux platform. It consists of a kernel module, several userspace management applications and some shell scripts and is normally used on high availability clusters...
and the cluster software Pacemaker, LIO allows the configuration of highly-available storage systems. RTSadmin, the management platform for LIO, supports easy setup and configuration of such HA arrays.
LIO is being developed by RisingTide Systems, located in the Silicon Valley, which manufactures storage systems and software. RisingTide Systems is a member of the Linux Solutions Group
Lisog
Lisog is a German open source non profit business development organization founded in 2005 in Stuttgart. Lisog has about 120 members and branch offices in Berlin, Hamburg, Vienna, Zurich, Palo Alto and Toronto. The members are providers, user companies, and scientific partners like universities.In...
(Lisog), where LIO provides the blocklevel storage component for the open source
Open source
The term open source describes practices in production and development that promote access to the end product's source materials. Some consider open source a philosophy, others consider it a pragmatic methodology...
reference stack.
Target
LIO has a modular and extensible architecture. The LIO SCSISCSI
Small Computer System Interface is a set of standards for physically connecting and transferring data between computers and peripheral devices. The SCSI standards define commands, protocols, and electrical and optical interfaces. SCSI is most commonly used for hard disks and tape drives, but it...
target core is independent of specific fabric modules or backstore types. This way, LIO can support any number of fabrics and backstores, and allows using them together at the same time. The LIO modules have gone upstream or are scheduled to go upstream into the Linux kernel as follows:
- Linux 2.6.38 (released on 3/14/2011): Generic multiprotocol target engine (including all backstores)
- Linux 2.6.39 (released on 5/18/2011): tcm_loop (can provide SCSI support on top of any raw hardware)
- Linux 3.0 (released on 7/21/2011): FCoEFibre Channel over EthernetFibre Channel over Ethernet is an encapsulation of Fibre Channel frames over Ethernet networks. This allows Fibre Channel to use 10 Gigabit Ethernet networks while preserving the Fibre Channel protocol...
(by Cisco) - Linux 3.1 (released on 10/24/2011): iSCSIISCSIIn computing, iSCSI , is an abbreviation of Internet Small Computer System Interface, an Internet Protocol -based storage networking standard for linking data storage facilities. By carrying SCSI commands over IP networks, iSCSI is used to facilitate data transfers over intranets and to manage...
- Linux 3.2: InfiniBandInfiniBandInfiniBand is a switched fabric communications link used in high-performance computing and enterprise data centers. Its features include high throughput, low latency, quality of service and failover, and it is designed to be scalable...
/SRPSCSI RDMA ProtocolIn computing the SCSI RDMA Protocol is a protocol that allows one computer to access SCSI devices attached to another computer via remote direct memory access . The SRP protocol is also known as the SCSI Remote Protocol. The use of RDMA makes higher throughput and lower latency possible than what...
(Mellanox HCAs) and IBM vSCSI (for the IBM pSeries) - Linux 3.3: Fibre ChannelFibre ChannelFibre Channel, or FC, is a gigabit-speed network technology primarily used for storage networking. Fibre Channel is standardized in the T11 Technical Committee of the InterNational Committee for Information Technology Standards , an American National Standards Institute –accredited standards...
(QLogicQLogicQLogic Corporation is an Aliso Viejo, California-based designer and supplier of storage networking, high performance computing networking, and converged infrastructure solutions...
HBAs) and advanced SCSISCSISmall Computer System Interface is a set of standards for physically connecting and transferring data between computers and peripheral devices. The SCSI standards define commands, protocols, and electrical and optical interfaces. SCSI is most commonly used for hard disks and tape drives, but it...
features
Initiator
RisingTide Systems also provides an open sourceOpen source
The term open source describes practices in production and development that promote access to the end product's source materials. Some consider open source a philosophy, others consider it a pragmatic methodology...
iSCSI
ISCSI
In computing, iSCSI , is an abbreviation of Internet Small Computer System Interface, an Internet Protocol -based storage networking standard for linking data storage facilities. By carrying SCSI commands over IP networks, iSCSI is used to facilitate data transfers over intranets and to manage...
initiator, called Core-iSCSI. Core-iSCSI supports a number of advanced iSCSI features, including, in particular, Multiple Connections per Session (MC/S) and Error Recovery Level 2 (ERL=2), which the standard Linux Open-iSCSI initiator doesn't support. This way, Core-iSCSI can drive increased availability, scalability and performance. Core-iSCSI also allows remote boot across an iSCSI
ISCSI
In computing, iSCSI , is an abbreviation of Internet Small Computer System Interface, an Internet Protocol -based storage networking standard for linking data storage facilities. By carrying SCSI commands over IP networks, iSCSI is used to facilitate data transfers over intranets and to manage...
SAN or WAN ("diskless boot").
See also
- Storage fabrics: iSCSIISCSIIn computing, iSCSI , is an abbreviation of Internet Small Computer System Interface, an Internet Protocol -based storage networking standard for linking data storage facilities. By carrying SCSI commands over IP networks, iSCSI is used to facilitate data transfers over intranets and to manage...
, Fibre ChannelFibre ChannelFibre Channel, or FC, is a gigabit-speed network technology primarily used for storage networking. Fibre Channel is standardized in the T11 Technical Committee of the InterNational Committee for Information Technology Standards , an American National Standards Institute –accredited standards...
, FCoEFibre Channel over EthernetFibre Channel over Ethernet is an encapsulation of Fibre Channel frames over Ethernet networks. This allows Fibre Channel to use 10 Gigabit Ethernet networks while preserving the Fibre Channel protocol...
, InfiniBandInfiniBandInfiniBand is a switched fabric communications link used in high-performance computing and enterprise data centers. Its features include high throughput, low latency, quality of service and failover, and it is designed to be scalable... - SCSISCSISmall Computer System Interface is a set of standards for physically connecting and transferring data between computers and peripheral devices. The SCSI standards define commands, protocols, and electrical and optical interfaces. SCSI is most commonly used for hard disks and tape drives, but it...
External links
- LIO Wiki (linux-iscsi.org)
- RisingTide Systems website
- RFC 3720: Internet Small Computer Systems Interface (iSCSI)
- RTS Director video