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Cisco SN 5400 Series Storage Routers

iSCSI Driver for AIX Frequently Asked Questions

Document ID: 30004

Updated: Nov 08, 2004

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Contents

Introduction

The term SN 5400 is used generically throughout this document to refer to any storage router product in the SN 5400 family (SN 5420, SN 5428-2, or SN 5428). There is a separate Frequently Asked Question (FAQ) document for each iSCSI driver and the SN 5400 itself. Typical subjects covered in these FAQs are installation questions, system requirements, and product compatibility.

This document refers to version 3.1.1 of the AIX driver. The majority of this information is applicable to newer or older versions of the driver. There may, however, be slight operational differences between driver versions, which may result in behaviors inconsistent with what is described in this document.

Q. How do I find out what version of the driver I am currently running?

A. The directions for finding the version of code you are running can be found in the Installation Notes section of the Release Notes for the Cisco iSCSI Driver for AIX.

Q. What is the most current version of the driver available?

A. The most current version of the driver can be found at the Cisco iSCSI Drivers ( registered customers only) page on the Cisco.com.

Q. Is there a README file associated with the driver?

A. Yes. The README file is included in the driver tar file. You can download the tar file from the Cisco iSCSI Drivers ( registered customers only) page on Cisco.com, and extract the README by untarring the file. The README contains information about the license agreement, driver installation, configuration instructions, a technical overview of the driver architecture, and general system requirements.

Q. How do I download and install the most current version of the driver?

A. The directions for downloading, installing, and uninstalling the driver can be found in the Installation Notes section of the Release Notes for the Cisco iSCSI Driver for AIX.

Q. What are the AIX system requirements for installing the driver?

A. The operating system requirements and patch requirement are described in the System Requirements section of the Release Notes for the Cisco iSCSI Driver for AIX.

Q. With which version(s) of AIX does the driver work?

A. The driver has been tested and works with the IBM AIX 4.3.3 operating environment. Both 32 bit and 64 bit versions of this operating system are supported.

Q. Does the driver work in a multiprocessor system?

A. The driver has been designed to work in all uniprocessor and multiprocessor environments. Systems with more than four processors have not been tested, however, there are no known limits in the driver that would prevent it from working in such a configuration.

Q. Which processor families are supported by the driver?

A. The driver has been tested only with the POWER3-II or POWER PC 604e family of processors, however, there are no known limits in the driver that would prevent it from working on hosts with a different family of processors.

Q. What are the known caveats with the current driver and which caveats have been resolved with the current driver?

A. The caveat information for all versions of the driver can be found in the Caveats section of the Release Notes for the Cisco iSCSI Driver for HP-UX 11.0.

Q. What version of the SN 5400 software is my driver compatible with?

A. Not all versions of driver code are interoperable with all versions of the SN 5400 code. To determine if your driver is interoperable with your SN 5400, use this table:

Driver Version SN 5428 Version Compatible
1.8.x 1.a.b Yes
1.8.x 2.a.b No
1.8.x 3.a.b No
2.x.y 1.a.b No
2.x.y 2.a.b Yes
2.x.y 3.a.b Yes
3.x.y 1.a.b No
3.x.y 2.a.b No
3.x.y 3.a.b Yes

Q. Is the Cisco driver interoperable with other non-Cisco iSCSI target devices?

A. The Cisco driver has been written, tested, and qualified for use in a Cisco SN 5400 storage router environment. Any other use of this driver is not covered by any expressed or implied warranty by Cisco. Cisco provides support for use of these drivers only in a Cisco SN 5400 environment.

Q. What Ethernet Network Interface Cards (NIC) and host applications have been tested with the driver and the Cisco SN 5400?

A. The list of equipment tested with the Cisco SN 5400 is included in the Interoperability Matrix document.

Q. What are the maximum number of Logical Unit Numbers (LUNs) per target supported by the driver?

A. The maximum number of LUNs per target is 256. This value is not user configurable.

Q. What is the maximum number of targets supported by the driver?

A. The maximum number of targets is 64 in driver version 2.1.2 or greater. Prior to 2.1.2, the maximum number of targets was eight. This value is not user configurable.

Q. Does the mapping of the SCSI target to the physical storage device remain the same from one reboot to the next (persistent target binding)?

A. Yes. The AIX driver version 2.1.2 or greater supports persistent target binding. A more detailed description of this feature is included in the Installation section of the driver README file.

Q. Where are the error or event messages from the iSCSI driver logged?

A. All iSCSI driver error and event messages are sent to the syslog. A more detailed description of the logging process is described in the Log Messages section of the driver README file.

Q. Where are the error or event messages from the iSCSI driver logged?

A. The iSCSI driver uses syslog to log messages. Based on the syslog configuration on the AIX host, messages are sent to the appropriate destination.

Q. How do I know the connection status of the iSCSI targets?

A. The utility lsiscsi can be used on the AIX system to get information about iSCSI devices discovered by the driver (both configured and unconfigured devices available to the system).

Q. How do I get a list of all the iSCSI devices discovered by the driver?

A. The 3.1.1 version of the AIX iSCSI driver has no utility that displays the connection status of the iSCSI targets. It is expected that this feature will be added in a future release of the driver.

Q. Why do I/Os to iSCSI devices fail when the network goes down for some time?

A. The value assigned to the variable conn_timeout governs the duration of network downtime which will cause I/Os directed to iSCSI devices to fail. This variable is user configurable. A more detailed description of the usage of this parameter is described in the Attributes of iSCSI Driver section of the driver README file.

Q. Are you required to restart the iSCSI driver if a new target is added to the SN 5400 when the driver is already connected to the SN 5400?

A. No. The iSCSI driver automatically configures the new target in the system provided access is granted to the AIX host system for the new target. A more detailed description of this process is described in the Activation of Dynamically Added LUNs section of the driver README file.

Q. How does the throughput performance of iSCSI compare to that of a native Fibre Channel (FC) Host Bus Adapter (HBA)?

A. The performance of iSCSI as compared to native FC depends on many factors. A report on the performance of the SN 5420 using a Windows NT host can be found on Cisco.com. There is not a report that addresses the performance specifically with the Linux driver.

Q. How does the latency of iSCSI compare to that of a native Fibre Channel (FC) Host Bus Adapter (HBA)?

A. The latency of iSCSI as compared to native FC depends on many factors. A report on the latency of the SN 5420 using a Linux host can be found on Cisco.com.

Related Information

Updated: Nov 08, 2004
Document ID: 30004