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LIO (Linux-IO) is the standard open-source storage Target in Linux. It supports all prevalent storage fabrics, including Fibre Channel (QLogic), FCoE, iEEE 1394, iSCSI, iSER (Mellanox InfiniBand), SRP (Mellanox InfiniBand), USB, vHost, etc.

The advanced feature set of LIO has made it the storage target of choice for many storage array vendors, for instance allowing them to achieve VMware® Ready certifications. Native support for LIO Target in QEMU/KVM, libvirt, and OpenStack™ makes it an attractive storage option for cloud deployments.

LIO includes targetcli, a management shell and API with a single namespace for all storage objects.

LIO and targetcli are developed by Datera, Inc., a data storage systems and software company located in the Silicon Valley.

Unified target

Fabric modules implement the frontend of the SCSI target.

• Fibre Channel - QLogic: released
• Fibre Channel over Ethernet (FCoE): released
• iEEE 1394: released
• IBM vSCSI for IBM System p: RC
• iSCSI (SCSI over IP): released
• iSER (Mellanox InfiniBand): development
• Loopback SCSI virtualization: released
• SRP (Mellanox InfiniBand): released
• USB Gadget: released
• vHost with QEMU/KVM virtio and virtio-scsi PV guests: released

Storage media independence

Backstores implement methods of accessing data on devices.

• Backstores: SATA, SAS, SCSI, SSD, FLASH, DVD, USB, ramdisk, etc.
• Virtualization of storage media; transparent mapping of I/O to LUNs
• No hard limits on number of LUNs/Target; maximum LUN size ¾PB

Architecture

The target engine implements the semantics of a SCSI target.

• High-performance, non-blocking, multithreaded architecture with SSE4.2 support and no single-point of failure
• CPU architectures: x86, ia64, Alpha, Cell, PPC, ARM, MIPS, etc.
• Distributions: CentOS, Debian, Fedora, openSUSE, RHEL, Scientific Linux, SLES, Ubuntu
• Platforms: PC architecture, Sony PS2/PS3, Raspberry Pi, Technologic TS-7800

Advanced SCSI feature set

• Persistent Reservations (PRs)
• Asymmetric Logical Unit Assignment (ALUA)
• Error Recovery Levels (ERL=0,1,2)
• Active/active task migration and session continuation (ERL=2)
• Protocol multiplexing, load-balancing and failover (MC/S)

The Target works with Initiators of the following operating systems:

• Microsoft: Windows® Server 2003/2008/R2 and Windows® XP/Vista/7
• Apple Mac OS X (via third-party initiator)
• Linux: RHEL 4/5/6, SLES 10.3/11, CentOS, Debian, Fedora, openSUSE, Ubuntu
• Unix: Solaris 10, OpenSolaris, HP-UX
• VMs: vSphere™ 5, Red Hat KVM, Microsoft Hyper-V, Oracle xVM/VirtualBox, Xen

The Target enables VMware Ready certifications (incl. vSphere™ 5). It also passes the Microsoft Windows® Server 2008 / R2 Failover Cluster compatibility test suites.

targetcli provides the fabric agnostic single-node management shell for LIO Unified Targets. targetcli aggregates and presents all SAN functionality via the RTSlib library and API [HTML][PDF] to the Unified Target.

RTS OS integrates the Unified Target and targetcli into a single-node Unified Storage operating system (Admin Manual). RTS OS supports VMware Ready certification, including VMware vSphere™ 5.

An RTS OS subscription provides access to additional RTS OS packages and update services.

RTS OS is currently being extended into RTS Live, a cluster storage operating system that is based on RTS Director.

LIO is designed from gound up to support highly available and cluster storage:

• Deeply embedded high availability (Network RAID1)
• Scale-out clusters and disaster recovery solutions

The Core-iSCSI Initiator is a high-end iSCSI Initiator that resolves a number of known issues with the Open-iSCSI standard Linux Initiator.

Core-iSCSI is available on Linux and Windows®, and it has been ported to a wide range of platforms and devices, including:

• Linksys OpenWRT (MIPS)
• Motorola ROKR E2 cell phone (XScale)
• Neuros OSD Set-top-box (ARM9)
• Nokia 770 and Nokia N800 Internet Tablets (ARM9 and Cortex)
• OpenMoko Neo1973 and OpenMoko Neo FreeRunner cell phones (ARM)

Datera, Inc. ported OCFS2 onto the Nokia Internet Tablets on top of the Core-iSCSI Initiator.

RTS Director is a distributed, highly-available cluster management framework. It comprises a shell, active library and API. The active library and API provide an extensible platform with a unified namespace to manage complex functionality, such as high-availability and cluster striping. The shell offers location-transparent access to all objects in the SAN. New functionality and devices can be added via plugin-modules.

RTS Director provides zero configuration. It is based on a symmetrically distributed architecture - there is no single point of failure, no cluster controller, no central database, etc. Nodes running the RTS Director automatically discover and join the cluster when coming up (demo video).

Fibre Channel | FCoE | InfiniBand | iSCSI | iSER | iSNS | iWARP | RTS OS | SCSI virtualization | SLP | SRP | targetcli | vHost