LIO

Architecture

SCSI target module

LIO has a modular structure around a central SCSI target module. The term SCSI Target is not only used in this context by service provider devices on a SCSI bus, but more generally for the commands receiving end of a SCSI connection. So the work from SCSI connections over networks without any physical SCSI bus. For these compounds, the SCSI target module is the service providing server in this case.

Back gate

In order to provide this service requires the SCSI target module storage media, which in turn can be SCSI target depending on version, but need not. The connection to a variety of storage media is performed by so-called back door, working as a backend to the SCSI target module. Back door can be connected via an interface to the abstraction of storage devices of Storage Hardware Abstraction Layer ( HAL S ) in the Linux kernel with the SCSI target module. The SCSI target module supports the SCSI-3 standard for all the back door. A special loopback module allows the integration of RAM disks or SSD storage. About the FILEIO module files can be linked from any file system as the storage medium.

Fabric modules

A Fabric Module ( eng. "tissue" or " structure " ) provides the services of the SCSI target module on a specific protocol. There are fabric modules for Fibre Channel, FCoE (Fibre Channel over Ethernet) SCSI over IP networks, and others. This can be called Storage Area Networks ( SAN) to build.

Initiator

In addition to the SCSI target is still provided by Datera also an open source iSCSI initiator names Core - iSCSI. A special feature is the support for multiple connections per session (multiple iSCSI connections per iSCSI session - MC / S). In this way, improved availability and performance is made possible. The default Linux iSCSI initiator does not support this feature. Core - iSCSI also allows booting from servers to an iSCSI SAN ( diskless boot).

Features

LIO supports the iSCSI standard and Persistent Reservations and ALUAs (Asymmetric Logical Unit Assignment ) of the SPC -4 SCSI standards.

Together with the replication software DRBD and Corosync cluster software can be built high-availability storage systems. The RTSdirector implementing a specific multi-node cluster with linear scalability.

The configuration is done via the Linux configfs, administration via a command - line tool ( RTSadmin ). With the release of version 2, it is possible to manage Fibre Channel, FCoE and InfiniBand configurations. The version 2 was dual licensed and the community version ' targetcli ' is released under AGPL.

LIO has been developed by the company Datera and is integrated by some manufacturers of storage appliances ( Buffalo, Netgear, Pure Storage, QNAP, Synology, etc.).