Introduction
iSER accelerates the iSCSI protocol by mapping the data transfer phases to Remote DMA (RDMA) operations. As a result an iSER initiator should be able to read and write data from an iSER target at high data rates with relatively low CPU utilization compared to iSCSI using TCP/IP. This project will implement both an iSER initiator and an iSER target. In addition, the project will implement an iSCSI port provider (iscsit) for COMSTAR adding an iSCSI transport option to the existing Fibre Channel and SAS support. The iSER target will be an extension of this iSCSI port provider.
To maximize the code sharing between iSER initiator and iSER target the current iSER design defines a component called "iSCSI Data Mover" (IDM). The iSCSI initiator and iSCSI target port provider will link against the IDM kernel module which will provide iSCSI connection services and a transport abstraction layer. iSER will be implemented beneath this abstraction layer allowing both initiator and target to use a single shared iSER implementation.
Based on this design the project will deliver the following components:
- iSCSI Initiator modified to use IDM
- iSCSI COMSTAR port provider (iscsit)
- iSCSI Data Mover kernel module (IDM)
- iSER transport plugin for IDM
Although the iSER protocol can be used with any RDMA-capable network, the scope of this project is currently limited to Infiniband.
Status
iSER integrated into build 112 and will be available in SXCE 112 and OpenSolaris 2010.02.
Documentation
- iSER Overview slides
- COMSTAR iSCSI Port Provider Design Document
- iSCSI Data Mover Design document
- iSER Transport Design document
- Proposed usage for itadm(1m) - updated 27-August-2008
- State machine diagrams for iscsit (last page is the new target state machine)