Introduction; Features - Chelsio Communications Terminator Series Installation And User Manual

Chapter X. iSCSI PDU Offload Target

Introduction

This section describes how to install and configure iSCSI PDU Offload Target software for use as
a key element in your iSCSI SAN. The software runs on Linux-based systems that use Chelsio or
non-Chelsio based Ethernet adapters. However, to guarantee highest performance, Chelsio
recommends using Chelsio adapters. Chelsio's adapters include offerings that range from
stateless offload adapters (regular NIC) to the full line of TCP/IP Offload Engine (TOE) adapters.
The software implements RFC 3720, the iSCSI standard of the IETF. The software has been fully
tested for compliance to that RFC and others and it has been exhaustively tested for
interoperability with the major iSCSI vendors.
The software implements most of the iSCSI protocol in software running in kernel mode on the
host with the remaining portion, which consists of the entire fast data path, in hardware when
used with Chelsio's TOE adapters. When standard NIC adapters are used the entire iSCSI
protocol is executed in software.
The performance of this iSCSI stack is outstanding and when used with Chelsio's hardware it is
enhanced further. Because of the tight integration with Chelsio's TOE adapters, this software has
a distinct performance advantage over the regular NIC. The entire solution, which includes this
software, Chelsio TOE hardware, an appropriate base computer system – including a high end
disk subsystem, has industry leading performance. This can be seen when the entire solution is
compared to others based on other technologies currently available on the market in terms of
throughput and IOPS.
1.1.

Features

Chelsio's iSCSI driver stack supports the iSCSI protocol in the Target mode. From henceforth
"iSCSI Software Entity" term refers to the iSCSI target.
The Chelsio iSCSI PDU Offload Target software provides the following high level features:
Expanded NIC Support
•
Chelsio TCP Offload Engine (TOE) Support
▪
T6/T5/T4 Based HBAs (T6/T5/T4xx Series cards)
•
Non-Chelsio
▪
Runs on regular NICs
Chelsio Terminator ASIC Support
•
Offloads iSCSI Fast Data Path with Direct Data Placement (DDP)
•
Offloads iSCSI Header and Data Digest Calculations
•
Offload Speeds at 1Gb, 10Gb, 25Gb, 40Gb and 100Gb
•
Offloads TCP/IP for NAS simultaneously with iSCSI
Target Specific features
•
Full compliance with RFC 3720
Chelsio Unified Wire for Linux 149