Multiple Connections per Session

The Linux SCSI Target Wiki

Multiple (iSCSI) connections per (iSCSI) session (MC/S) means creating multiple communication paths in a single session (I_T Nexus), i.e. across TCP, SCTP, iSER, and/or RCaP transport connections.

Architectural session command ordering is preserved across those communication paths. Session-wide architectural command ordering (defined by the CmdSN) is preserved per RFC 3720. This is to ensure in-order delivery of tasks from an SCSI Initiator port to an SCSI target port as defined by the SCSI Architecture Model, in which iSCSI provides the SCSI transport.

Contents 1 Linux Compatibility 2 Standards compliance 3 See also 4 External links

Linux Compatibility

• Core-iSCSI: supported, stable
• Open-iSCSI: not supported

Standards compliance

The requirements as defined by RFC 3720 for non-ERL dependent MC/S support are not limited to the following:

• Add additional connections on the fly with active+inactive IO (non-leading login)
• Remove connections on the fly with active+inactive IO (explict logout)
• Remove connections on the fly on a different connection with active+inactive IO (different CID explict logout)
• Restart session+connections during single connection failure (session reinstatement)
• Multiple connection sessions to the same and different network portals (iSCSI trunking)

See also

• LinuxIO
• SCSI: Persistent Reservations (PRs), Asymmetric Logical Unit Assignment (ALUA), Error Recovery Level (ERL)
• Fabric modules: FCoE, Fibre Channel, iSCSI, iSER, SRP and vHost
• Management: targetcli
• KVM (with some MC/S performance data)

External links

• RFC 3720: Internet Small Computer Systems Interface (iSCSI)