ISCSI Extensions for RDMA

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LIO Target
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InfiniBand iSER fabric module
Original author(s) Nicholas Bellinger
Developer(s) Datera, Inc.
Written in C
Operating system Linux
Type Fabric module
License GNU General Public License
Website datera.io
See Target for a complete overview over all fabric modules.

iSCSI Extensions for RDMA (iSER) is a network protocol that extends iSCSI to use RDMA.

Contents

Overview

iSER permits data to be transferred directly into and out of remote SCSI computer memory buffers without intermediate data copies by using RDMA. RDMA is supported on InfiniBand networks, by RoCE on "lossless" (DCB) Ethernet networks, and by iWARP enhanced TOE NICs over standard Ethernet networks.

An InfiniBand iSER fabric module for the Unified Target is currently being implemented as a joint development effort between Datera, Inc. and Mellanox. It is planned for release with Linux kernel version 3.10.

History

An RDMA consortium was announced on May 31, 2002 with a goal of product implementations by 2003.[1] The consortium released their proposal in July, 2003.[2] The protocol specifications were published as drafts in September 2004 in the Internet Engineering Task Force and issued as RFCs in October 2007.[3][4] The OpenIB Alliance was renamed in 2007 to be the OpenFabrics Alliance, and then released an open source software package.[5]

Cookbook

The iser-target implementation uses the existing iscsi-target control plane, with a special iser bit per network portal context to enable iser-target operation. Instructions for basic configuration can be found at ISCSI

Enable iser-target per network portal

Once the necessary rtslib, targetcli and lio-utils userspace changes are in place, enabling iser-target operation is done on a per network portal basis.

iser-target uses RDMA-CM + IPoIB to initiate the iser login process, so RDMA capable hardware needs to have an ibX configured with a IP address in order to be used by iser-target code.

The configured ibX interface should look like:

# ifconfig ib0
ib0       Link encap:InfiniBand  HWaddr 80-00-00-48-FE-80-00-00-00-00-00-00-00-00-00-00  
          inet addr:10.100.0.1  Bcast:10.100.0.255  Mask:255.255.255.0
          UP BROADCAST MULTICAST  MTU:4092  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:256 
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

and will be accessable within targetcli to configure as a traditional iscsi-target network portal:

/iscsi/iqn.20...e1d3417/tpgt1> ls
o- tpgt1 ............................................................. [enabled]
  o- acls ............................................................. [0 ACLs]
  o- luns .............................................................. [1 LUN]
  | o- lun0 .................................... [rd_mcp/large_rd_mcp (ramdisk)]
  o- portals ....................................................... [0 Portals]
/iscsi/iqn.20...e1d3417/tpgt1> ./portals create 10.100.0.1 
Using default IP port 3260
Successfully created network portal 10.100.0.1:3260.
Entering new node /iscsi/iqn.2003-01.org.linux-iscsi.tifa.x8664:sn.f3b21e1d3417/tpgt1/portals/10.100.0.1:3260
/iscsi/iqn.20....100.0.1:3260> ls
o- 10.100.0.1:3260 ......................................... [OK, iser disabled]

After the ibX interface network portal has been created, iser-target operation is enabled within each network portal context with 'iser_enable':

/iscsi/iqn.20....100.0.1:3260> iser_enable 
iser operation has been enabled
/iscsi/iqn.20....100.0.1:3260> ls
o- 10.100.0.1:3260 .......................................... [OK, iser enabled]
/iscsi/iqn.20....100.0.1:3260> 

RFCs

See also

Notes

  1. "Open Consortium Developing Specifications for Remote Direct Memory Access Over TCP/IP Networks". press release. 2002-05-31. 
  2. Mike Ko, et al. (July 2003). "iSCSI Extensions for RDMA Specification (Version 1.0)". 
  3. M. Ko et al. (October 2007). "Internet Small Computer System Interface (iSCSI) Extensions for Remote Direct Memory Access (RDMA)". RFC 5046. 
  4. M. Chadalapaka et al. (October 2007). "DA: Datamover Architecture for the Internet Small Computer System Interface (iSCSI)". RFC 5047. 
  5. "OpenFabrics Alliance". official web site. 

Wikipedia entries

External links

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