Table Of Contents
Release Notes for Cisco iSCSI Driver for AIX Version 1.8.1
May 3, 2002
Note You can find the most current documentation on Cisco.com. This set of electronic documents may contain updates and modifications made after the hard-copy documents were printed.
These release notes support Cisco iSCSI Driver for AIX version 1.8.1.
For a list of software caveats that apply to version 1.8.1, see the "Open Caveats" section. The caveats are updated for every maintenance version and are located on Cisco.com and the Documentation CD-ROM.
These Release Notes describe the following topics:
The Cisco iSCSI Driver for AIX provides an IP host with the ability to access storage through an IP network. The iSCSI driver uses iSCSI protocol to transport SCSI requests and responses over an IP network between the IP host and a Cisco SN 5420 Storage Router.
Architecturally, the iSCSI driver combines with the IP host TCP/IP stack, network drivers, and network interface cards (NICs) to provide the same functions as a SCSI or a Fibre Channel adapter driver with a host bus adapter (HBA).
The iSCSI driver provides a transport for SCSI requests and responses for storage devices; however, instead of providing a transport for directly attached devices, the driver transports the SCSI requests and responses between the server and a Cisco SN 5420 Storage Router via an IP network. The SN 5420 Storage Router, in turn, transports SCSI requests and responses between it and the storage devices attached to it.
Once the iSCSI driver is installed, the server will proceed with a discovery process for iSCSI storage devices as follows:
Step 1 The iSCSI driver requests available iSCSI targets from the storage router.
Step 2 The storage router sends available iSCSI target names to the server.
Step 3 The server logs into the iSCSI targets.
Step 4 The storage router accepts the server login and sends target identifiers.
Step 5 The server queries targets for device information.
Step 6 Targets respond with device information.
Step 7 The server creates a table of internal devices.
The Cisco iSCSI Driver for AIX provides IP access to a maximum of eight remote SCSI targets, with each target capable of supporting 32 LUNs.
Note The iSCSI protocol is an IETF-defined protocol for IP storage (ips). For more information about the iSCSI protocol, refer to the IETF standards for IP storage at http://www.ietf.org.
This section describes the system requirements for version 1.8.1 and includes the following information:
Operating System Requirements
The Cisco iSCSI Driver for AIX requires an AIX kernel version 4.3.3. The driver supports single-processor and multiprocessor machines. For multiprocessor machines the driver supports up to four processors.
Creating Logical Volumes and Mounting Filesystems
•If iSCSI disks are part of logical volume groups, ensure that the logical volume groups are not automatically activated at system reboot. When logical volume groups are automatically activated, the activation occurs before the network is configured and the iSCSI disks are discovered.
•If filesystems are installed on iSCSI devices, ensure that the filesystems are not automatically mounted at system restart. When filesystems are automatically mounted, the action occurs before the network is configured and the iSCSI devices are discovered. List the iSCSI partitions in the /etc/fstab.iscsi file. The "init" scripts will automatically mount and unmount these partitions.
•If you have layered mounts, ensure that the top-level filesystem is placed first in the /etc/fstab.iscsi file. For example, if you configure two filesystems, iscsi1 and iscsi1/iscsi2, ensure that the entry for iscsi1 in the /etc/fstab.iscsi file precedes the entry for iscsi1/iscsi2.
All filesystems on iSCSI devices must be unmounted before the iSCSI driver is stopped. If the iSCSI driver stops while iSCSI devices are mounted, buffered writes may not be committed to disk and filesystem corruption may occur.
Stop all applications using the iSCSI filesystems and run the iSCSI shutdown script (/etc/iscsi.clean rem). The iSCSI shutdown script will try to unmount filesystems listed in /etc/fstab.iscsi.
Caution If the iSCSI filesystems are in use when the iSCSI shutdown script is run, the script will fail. The applications using the filesystems must be stopped and the script must be run again. Filesystems not listed in /etc/fstab.iscsi will not be automatically unmounted.
Changes to iSCSI device attributes are not retained over a system reboot or iSCSI driver restart. You must restore the desired iSCSI device attributes
Enabling Reserve / Release Proxy Feature
If the Cisco iSCSI Driver for AIX connects to a SCSI routing instance running in an SN 5420 Storage Router configured for high availability, the SCSI routing instance must be configured with the Reserve / Release proxy feature enabled. Use the following CLI command on the SN 5420 to enable this feature:
set scsirouter name reserveproxy enable passthru no
If a failover occurs and the Reserve / Release proxy feature is not enabled, the AIX server's applications may fail with a "reservation conflict" message.
Note When the Reserve / Release proxy feature is enabled, IP host clustering may fail to function as expected.
The iSCSI Driver for AIX consists of components in the AIX kernel and user level utility, and all log messages are sent to syslog. Message destinations are based on the syslogd configuration for the AIX host. Messages from the iSCSI Driver for AIX can be received at the following facilities:
For example, the following entries in /etc/syslog.conf send all kernel message to the console and send all user messages to /usr/admin/ras/iscsi.log:kern.debug /dev/consoleuser.debug /usr/adm/ras/iscsi.log
SN 5420 Storage Router Software Requirements
The iSCSI Driver for AIX version 1.8.1 can connect to a Cisco SN 5420 Storage Router running software release 1.1.x; this driver cannot connect to a Cisco SN 5420 Storage Router running software release 2.1.x.
Note If the iSCSI Driver for AIX version 1.8.1 connects to an SN 5420 Storage Router running software release 1.1.8, LUNs may intermittently appear offline to the IP host when SCSI routing instances are stopped and restarted. If this occurs, retry the LUN discovery/activation process on the IP host. For more details about this situation, access Cisco.com as described in the section "Cisco.com" at the end of this document and reference SN 5420 caveat CSCdx23526.
Obtaining the iSCSI Driver and Updated Storage Router Software
From time to time, Cisco releases updated versions of storage router software and iSCSI drivers. Updated versions of storage router software and the Cisco iSCSI drivers, accompanying readme files, release notes and example configuration file are available for download.
If you are a registered Cisco.com user, you can download storage router software and iSCSI drivers. If you are a non-registered Cisco.com user, you can download only iSCSI drivers.
You can access software by following these instructions:
Step 2 At the Software Center web page, under Software Products & Downloads, click Storage Networking Software.
Step 3 At the Storage Networking Software web page, click the appropriate link for your software.
Step 4 At the software download web page, click the file that you want to download. Another software download web page will be displayed. Follow the instructions on that and any subsequent web pages to download the software.
Step 5 To install and configure storage router software, see the appropriate SN 5420 Storage Router software configuration guide and release notes. To install and configure an iSCSI driver, see the readme file that accompanies the iSCSI driver (in the downloaded driver archive file) and the appropriate release notes.
Uninstalling iSCSI Driver Software
To uninstall the iSCSI driver software, follow these instructions:
Step 1 Stop all applications using iSCSI devices. (The iSCSI shutdown script invoked in the following step will fail if it finds a device in use.)
Step 2 Unmount all iSCSI filesystems and stop the iSCSI driver by running the iSCSI shutdown script. For example:/etc/iscsi.clean rem
Step 3 Use SMIT to remove the driver, or remove the driver manually. For example:installp -u sn5420.rte
The /etc/iscsi.conf file is saved as /etc/iscsi.conf.SAVE. The /etc/fstab.iscsi file is saved as /etc/fstab.iscsi.SAVE.
Step 4 (Optional) If you added an entry to the /etc/rc.shutdown script to invoke /etc/iscsi.clean shutdown, remove that entry.
If connectivity to an iSCSI target is lost for more than 30 seconds, I/O to the target will fail. At that point, write data will be lost unless the application can handle write errors (i.e. with repeated retries until the I/O succeeds after the link comes up). If the writes are to mounted filesystems, the lost data may be filesystem metadata, which could cause filesystem corruption. If "fsck" is not run before using the filesystem after the connection is restored, system panic may occur.
Stop all I/O and unmount filesystems before doing anything that will cause long term loss of connectivity to active iSCSI targets. This includes activities such as removing network cables, SCSI routing instance configuration changes and stopping a SCSI routing instance. If long term loss of connectivity occurs unexpectedly, stop all I/O and correct the condition. After connectivity is restored, run "fsck" on the affected filesystems before re-mounting them.
This document lists caveats for Cisco iSCSI Driver for AIX version 1.8.1. Caveats describe unexpected behavior or defects in iSCSI software versions. Severity 1 caveats are the most serious caveats; severity 2 caveats are less serious.
This document describes open severity 1 and 2 caveats and selected caveats of other severities. For a more complete list of caveats against this release, access Cisco.com as described in the section "Cisco.com" at the end of this document.
Note If you have an account with Cisco.com, you can use Bug Navigator II to find caveats of any severity for any version. You can reach Bug Navigator II on Cisco.com at Service & Support:
If the /etc/iscsi.conf file contains IP addresses for multiple SCSI routing instances, only the first entry is used. The remaining entries are ignored.
Workaround: Configure a single SCSI routing instance to support the required targets for the AIX iSCSI driver. The SCSI routing instance can be configured in an SN 5420 Storage Router that is configured either in a cluster or as a stand-alone storage router.
The following sections describe the related documentation available for the Cisco iSCSI Driver for AIX version 1.8.1 and the Cisco SN 5420 Storage Router. These documents consist of the iSCSI driver release notes, readme and example configuration files, and the storage router hardware installation and software configuration guides.
The storage router hardware installation and software configuration documentation sets are available as printed manuals or electronic documents. The iSCSI driver readme file and example configuration file are available in electronic format, as part of the software download package. See the "Obtaining the iSCSI Driver and Updated Storage Router Software" section for details.
This Release Notes document is the only document specific to Cisco iSCSI Driver for AIX version 1.8.1. It is located on Cisco.com and the Documentation CD-ROM.
Each release of storage router software includes an associated Release Notes document, which is also available as an electronic document on Cisco.com and the Documentation CD-ROM.
Refer to the Cisco SN 5420 Storage Router Hardware Installation Guide for storage router hardware installation procedures. This document is available as a printed manual. It is also available as an electronic document on Cisco.com and the Documentation CD-ROM.
Refer to the Cisco SN 5420 Storage Router Software Configuration Guide Release 1.1 for storage router software configuration information and procedures. This document is available as a printed manual. It is also available as an electronic document on Cisco.com and the Documentation CD-ROM.
For documentation on the storage router web-based GUI, refer to the SN 5420 Storage Router web-based GUI online Help system.
Service and Support
For service and support for a product purchased from a reseller, contact the reseller, who offers a wide variety of Cisco service and support programs described in "Service and Support" of Cisco Information Packet shipped with your product.
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For service and support for a product purchased directly from Cisco, use Cisco.com.
Software Configuration Tips on the Cisco TAC Home Page
A variety of Cisco SN 5420 Storage Router software and iSCSI driver installation, configuration and usage tips are available on the Cisco Technical Assistance Center (TAC) Web Site.
You can access "tech tips" by following these instructions:
Step 2 At the Cisco Routers web page, under Cisco SN 5420 Storage Router Software, click Product Support.
Step 3 At the Cisco SN 5420 Storage Router Product Support web page, click the appropriate links for additional information about installing and configuring SN 5420 Storage Router software and iSCSI drivers.
The following sections explain how to obtain documentation from Cisco Systems.
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Obtaining Technical Assistance
Cisco provides Cisco.com as a starting point for all technical assistance. Customers and partners can obtain documentation, troubleshooting tips, and sample configurations from online tools by using the Cisco Technical Assistance Center (TAC) Web Site. Cisco.com registered users have complete access to the technical support resources on the Cisco TAC Web Site.
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Cisco.com is a highly integrated Internet application and a powerful, easy-to-use tool that provides a broad range of features and services to help you to
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You can self-register on Cisco.com to obtain customized information and service. To access Cisco.com, go to the following URL:
Technical Assistance Center
The Cisco TAC is available to all customers who need technical assistance with a Cisco product, technology, or solution. Two types of support are available through the Cisco TAC: the Cisco TAC Web Site and the Cisco TAC Escalation Center.
Inquiries to Cisco TAC are categorized according to the urgency of the issue:
•Priority level 4 (P4)—You need information or assistance concerning Cisco product capabilities, product installation, or basic product configuration.
•Priority level 3 (P3)—Your network performance is degraded. Network functionality is noticeably impaired, but most business operations continue.
•Priority level 2 (P2)—Your production network is severely degraded, affecting significant aspects of business operations. No workaround is available.
•Priority level 1 (P1)—Your production network is down, and a critical impact to business operations will occur if service is not restored quickly. No workaround is available.
Which Cisco TAC resource you choose is based on the priority of the problem and the conditions of service contracts, when applicable.
Cisco TAC Web Site
The Cisco TAC Web Site allows you to resolve P3 and P4 issues yourself, saving both cost and time. The site provides around-the-clock access to online tools, knowledge bases, and software. To access the Cisco TAC Web Site, go to the following URL:
All customers, partners, and resellers who have a valid Cisco services contract have complete access to the technical support resources on the Cisco TAC Web Site. The Cisco TAC Web Site requires a Cisco.com login ID and password. If you have a valid service contract but do not have a login ID or password, go to the following URL to register:
If you cannot resolve your technical issues by using the Cisco TAC Web Site, and you are a Cisco.com registered, you can open a case online by using the TAC Case Open tool at the following URL:
If you have Internet access, it is recommended that you open P3 and P4 cases through the Cisco TAC Web Site.
Cisco TAC Escalation Center
The Cisco TAC Escalation Center addresses issues that are classified as priority level 1 or priority level 2; these classifications are assigned when severe network degradation significantly impacts business operations. When you contact the TAC Escalation Center with a P1 or P2 problem, a Cisco TAC engineer will automatically open a case.
To obtain a directory of toll-free Cisco TAC telephone numbers for your country, go to the following URL:
Before calling, please check with your network operations center to determine the level of Cisco support services to which your company is entitled; for example, SMARTnet, SMARTnet Onsite, or Network Supported Accounts (NSA). In addition, please have available your service agreement number and your product serial number.
This document is to be used in conjunction with the documents listed in the "Related Documentation" section.
Copyright © 2002, Cisco Systems, Inc.
All rights reserved.