Table Of Contents
Release Notes for Cisco iSCSI Driver Version 2.1.4 for Sun Solaris 2.6 or Sun Solaris 7 or 8
August 8, 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 version 2.1.4 for Sun Solaris 2.6, and Sun Solaris 7 and 8.
For a list of software caveats that apply to version 2.1.4, see the "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 iSCSI Driver for Sun Solaris 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 host and a Cisco SN 5400 Series system.
Architecturally, the iSCSI driver combines with the host TCP/IP stack, network drivers, and NICs to provide the same functions as a SCSI 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 IP host and a Cisco SN 5400 Series system via an IP network. The SN 5400 Series system, in turn, transports SCSI requests and responses between it and the storage devices attached to it.
Once the iSCSI driver is installed, the IP host will proceed with a discovery process for iSCSI storage devices as follows:
Step 1 The iSCSI driver requests available iSCSI targets from the SCSI routing instances in the SN 5400 Series systems listed in the configuration file /etc/iscsi.conf, in the order that they appear.
Step 2 Each SN 5400 Series system sends available iSCSI target names to the iSCSI driver.
Step 3 The iSCSI discovery daemon looks up each discovered target in the /etc/iscsi_bindings file. If an entry exists in the file for a target, the corresponding Solaris target ID is assigned to the target; if no entry exists for a target, the smallest available Solaris target ID is assigned and an entry is written to the /etc/iscsi_bindings file. The iSCSI driver logs into the first 64 iSCSI targets it discovers, ignoring any remaining targets.
Step 4 The SN 5400 Series system accepts the login and sends target identifiers.
Step 5 The Solaris IP host queries targets for device information.
Step 6 Targets respond with device information.
Step 7 The Solaris IP host creates a table of internal devices.
The iSCSI Driver for Sun Solaris provides IP access to a maximum of 64 remote SCSI targets, with each target capable of supporting 256 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 2.1.4 and includes the following information:
Operating System Requirements
•The iSCSI Driver for Sun Solaris runs only on SPARC processor-based machines.
•The iSCSI Driver for Sun Solaris requires either Sun Solaris version 2.6 or Sun Solaris 7 or 8, with all Sun-recommended patches installed for the version being used.
•The iSCSI Driver for Sun Solaris supports both single and multiple processor machines.
•To ensure the best performance for the iSCSI driver, the extended windowing feature of TCP should be enabled on all IP hosts connecting to the SN 5400 Series system. In general, a larger window size enhances SN 5400 Series system throughput performance.
•To maximize performance, the receive and transmit flow control feature of the Gigabit Ethernet driver should be enabled on all IP hosts connecting to the SN 5400 Series system. If the IP hosts or the SN 5400 Series systems are connected to any Ethernet switches, the receive and transmit flow control attributes should be enabled on each of the connected switch ports.
•If you are using a 3Com Gigabit Ethernet Server network interface card in the IP host, the minimum supported revision level is "B" (3C985B-SX). Using a card with a lower revision level will significantly decrease performance.
No iSCSI device can be mounted until after the iSCSI daemon has started and logged into the appropriate iSCSI targets in the Cisco SN 5400 Series system. The iSCSI init.d script looks for entries with the "mount at boot" field set to "iscsi" in the /etc/vfstab file, and attempts to mount those entries after the iSCSI daemon starts. This allows iSCSI devices to be automatically mounted as early as possible in the boot process.
For example, the following /etc/vfstab entries will fsck and mount the two iSCSI devices specified:#device device mount FS fsck mount mount#to mount to fsck point type pass at boot options/dev/dsk/c1t5d0s6 /dev/rdsk/c1t5d0s6 /mnt/t5 ufs 1 iscsi -/dev/dsk/c1t6d0s6 /dev/rdsk/c1t6d0s6 /mnt/t6 ufs 1 iscsi -
Note Due to network delays, targets may not always become available in the same order. This means that the order in which iSCSI devices are mounted may vary, and may not match the order of the devices listed in /etc/vfstab. You should not assume that mounts of iSCSI devices will occur in any particular order.
The "mount at boot" field in /etc/vfstab should never be set to "yes" for an iSCSI device, because the standard Solaris boot sequence mounts devices before the network is available. Mounts of iSCSI devices with the "mount at boot" field set to "yes" fail because the iSCSI devices are not available that early in the boot process. If a mount fails, a maintenance shell will start and the Solaris boot process will not complete until the shell is exited. A user at the console must exit from the shell to cause the boot process to complete without the listed devices mounted.
All iSCSI devices must be unmounted before the iSCSI driver stops. If the iSCSI driver stops while iSCSI devices are mounted, buffered writes may not be committed to disk and filesystem corruption may occur. Because Solaris will not unmount devices that are being used by a running process, all processes using the iSCSI devices must be killed before the devices can be unmounted.
The init.d script will attempt to kill all processes using iSCSI devices by sending them SIGTERM and ILL. The init.d script then unmounts all iSCSI devices, and kills the iSCSI daemon, terminating all connections to iSCSI devices.
Note The init.d script may not be able to successfully unmount filesystems because they are in use by processes that cannot be killed. Best practice is to manually stop all applications using the filesystem before stopping the driver.
Persistent Target Bindings
Persistent target binding ensures that a Solaris SCSI target always maps to the same physical storage device across system restarts. The iSCSI daemon stores bindings of iSCSI target iSCSI Names (or WWUIs) to Solaris target IDs in the file /etc/iscsi_bindings.
If any entry exists for a discovered target, the Solaris target ID from the entry is assigned to the target. If no entry exists for a discovered target, an entry is written to the file.
The iscsi_bindings file contains the Solaris target ID, the discovery address, and the iSCSI Name (or WWUI) of the iSCSI target, as shown in the following example:TargetId DiscoveryAddress TargetName0 10.100.100.156 iqn.1987-05.com.cisco.00.7e9d6f942e45736be69cb65c4c22e54c.disk_one1 10.100.100.156 iqn.1987-05.com.cisco.00.4d678bd82965df7765c788f3199ac15f.disk_two
A discovery connection to each DiscoveryAddress remains open; new targets that become available to the Solaris host after the driver is started are automatically logged into and added to the iscsi_bindings file (if no entry currently exists).
To use these new targets, Solaris administrative command, such as drvconfig, disks, or tapes, must be issued to add the required /dev entries. If the required target and LUN entries for the new target do not exist in /kernel/drv/sd.conf, you may have to add them and reboot the system before you can access the target.
The /etc/iscsi_bindings file contains persistent entries for all iSCSI targets ever logged into from this host. If a target is no longer available to a host, you can stop the iSCSI driver and manually edit the iscsi_bindings file and remove the entry so the obsolete target no longer consumes a Solaris target ID.
For more information about the iscsi-bindings file and persistent target binding, see the iSCSI driver readme file.
Starting and Stopping the iSCSI Driver
It is possible to manually stop and start the iSCSI driver. This may be necessary if you want to make configuration changes without rebooting the Solaris system. When stopping the iSCSI driver, the init.d script will attempt to unmount iSCSI devices. Because the init.d script may not be able to unmount busy filesystems, best practice is to manually stop all applications that are using iSCSI filesystems before stopping the driver.
To manually stop the iSCSI driver, enter:/etc/init.d/iscsi stop
To manually start the iSCSI driver, enter:/etc/init.d/iscsi start
Caution When installing the iSCSI driver, do not manually stop and restart the iSCSI driver. Always reboot the Solaris system after doing a "pkgadd" of the driver.
All iSCSI devices should be unmounted prior to a system shutdown.
The Solaris /usr/sbin/reboot command should not be used to reboot the system while iSCSI devices are mounted. This reboot command will not execute the iSCSI shutdown script in /etc/rc0.d, and file system corruption can occur.
To safely reboot the Solaris system, use the following shutdown command:/usr/sbin/shutdown -i 6
SN 5400 Series System Software Requirements
The iSCSI Driver version 2.1.4 for Sun Solaris is compatible with a Cisco SN 5400 Series system running software release 2.1.1 or later; this driver is not compatible with any Cisco SN 5420 Storage Router running software release 1.1.x.
Obtaining the iSCSI Driver and Updated SN 5400 Series System Software
From time to time, Cisco releases updated versions of SN 5400 Series system software and iSCSI drivers. Updated versions of SN 5400 Series system software and the Cisco iSCSI drivers, accompanying readme files, release notes and example configuration files are available for download.
You must be a registered Cisco.com user to download Cisco SN 5400 Series system software and iSCSI drivers.
You can access software by following these instructions:
Step 1 At http://www.cisco.com, log in to Cisco.com. Under Service & Support, click Software Center.
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 link for the software that you want to download. Clicking the link will cause another web page to 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 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.
Upgrading to a New Version
To upgrade to a new version of iSCSI driver software, follow these instructions.
Note You must be super-user (root) to install and configure the iSCSI driver package.
Step 1 Unmount all iSCSI file systems and stop the old iSCSI driver. To manually stop the iSCSI driver, enter:/etc/init.d/iscsi stop
Step 2 Save the current /etc/iscsi.conf and /kernel/drv/sd.conf configuration files to another location.
Step 3 Remove the old iSCSI package.pkgrm CSCOiscsi
Step 4 Copy the solaris_iscsi_<version>.tar.Z file to a working directory, such as /usr/local/iscsi. Make the directory if it does not exist. If the directory does exist, remove any files from a previous installation. The <version> is the three digit version, such as 2.1.4. For example:mkdir /usr/local/iscsicp /tmp/solaris-iscsi-2.1.4.tar.Z /usr/local/iscsi
Step 5 Change to the working directory created in Step 4, and untar the file using the tar command. For example:cd /usr/local/iscsiuncompress solaris-iscsi-2.1.4.tar.Ztar xvf solaris-iscsi-2.1.4.tar
Your working directory (/usr/local/iscsi in the examples above) now contains the iSCSI driver package. The package contains the drivers and associated files.
Step 6 Add the package.cd /usr/local/iscsipkgadd -d . CSCOiscsi
The package installation instructions note that the system must be rebooted. Continue with the following configuration steps before rebooting the system.
Step 7 Compare the current /etc/iscsi.conf file to the iscsi.conf file saved in Step 2. Update it with any new information from the upgrade file, and save it as /etc/iscsi.conf. (If an /etc/iscsi.conf file exists when the new iSCSI driver package is installed, it is not overwritten or deleted. The updated iscsi.conf file is installed as iscsi.conf.<version>; for example iscsi.conf.2.1.4.)
Step 8 Compare the current /kernel/drv/sd.conf to the sd.conf file saved in Step 2. Update it with any new information from the upgrade file, and save it as /kernel/drv/sd.conf.
Step 9 Reboot the system to start and reload the iSCSI driver.
Step 10 Rebooting the system in Step 9 should reconfigure devices and load the iSCSI driver. Once the iSCSI daemon starts, execute the commands in Example 1 or Example 2 to reconfigure the SCSI disk devices:
Example 1 Configure the /devices Directory and Create /dev Entriesdrvconfigdisks
Example 2 Solaris Administration Command for /dev and /devicesdevfsadm
See the readme file for additional information about installing or upgrading iSCSI driver software.
Uninstalling iSCSI Driver Software
To uninstall the iSCSI driver software, follow these instructions:
Step 1 Unmount all iSCSI devices and stop the driver. For example:/etc/init.d/iscsi stop
You may want to save the /etc/iscsi.conf configuration file to another location before proceeding with the removal process.
Step 2 Remove the iSCSI driver. You must have super-user (root) authority to remove the driver.pkgrm CSCOiscsi
All configuration files installed by the package will be deleted.
Caveats describe unexpected behavior or defects in iSCSI software versions. Severity 1 caveats are the most serious caveats; severity 2 caveats are less serious.
•The "Open Caveats" section describes open severity 1 and 2 caveats that apply to the current version and may apply to previous versions.
•The "Resolved Caveats" section describes severity 1 and 2 caveats resolved in this version, but open in previous versions.
Within the sections, the caveats are sorted alphanumerically by caveat number.
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: http://www.cisco.com/pcgi-bin/Support/Bugtool/launch_bugtool.pl.
While running traffic to a tape drive, the Gigabit Ethernet connection from a Sun Solaris IP host to the SN 5420 Storage Router may be intermittently dropped and re-added for no apparent reason.
Workaround: None. However, the user should check the connections between the hosts and the SN 5420, and verify that the flow control is consistent between the hosts, switches, and the SN 5420s.
All of the caveats listed in this section are resolved in the iSCSI driver version 2.1.4 for Sun Solaris.
When the iSCSI driver loses communication with the SN 5400 Series system, the iSCSI driver holds a data packet until the SCSI timer expires, or communication is re-established. Because the Solaris sd driver attempts several retries for each aborted command, Powerpath failover can be significantly delayed.
Workaround: None. This problem is resolved in the iSCSI driver version 2.1.4 through the implementation of the ConnFailTimeout parameter in the /etc/iscsi.conf file. For more information about the /etc/iscsi.conf file format and the ConnFailTimeout parameter, see the iSCSI driver readme file.
The following sections describe the related documentation available for the iSCSI Driver version 2.1.4 for Sun Solaris and the Cisco SN 5400 Series systems. These documents consist of the iSCSI driver release notes, readme and example configuration files, and the SN 5400 Series system hardware installation and software configuration guides.
The SN 5400 Series system 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 SN 5400 Series System Software" section for details.
This Release Notes document is the only document specific to the iSCSI Driver version 2.1.4 for Sun Solaris. It is located on Cisco.com and the Documentation CD-ROM.
Each release of SN 5400 Series system 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 appropriate SN 5400 Series system hardware installation guide for hardware installation procedures. The Cisco SN 5420 Storage Router Hardware Installation Guide provides hardware installation procedures for SN 5420 Storage Routers. The Cisco SN 5428 Storage Router Hardware Installation Guide provides hardware installation procedures for SN 5428 Storage Routers. These documents are available as printed manuals. They are also available as electronic documents on Cisco.com and the Documentation CD-ROM.
Refer to the appropriate SN 5400 Series system software configuration guide for software configuration information. The Cisco SN 5420 Storage Router Software Configuration Guide Release 2.1 provides configuration information for SN 5420 Storage Routers. The Cisco SN 5428 Storage Router Software Configuration Guide (Release 2.2 or later) provides configuration information for SN 5428 Storage Routers. These documents are available as printed manuals. They are also available as electronic documents on Cisco.com and the Documentation CD-ROM.
For documentation on the SN 5400 Series system web-based GUI, refer to the SN 5400 Series system 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.
Note If you purchased your product from a reseller, you can access Cisco.com as a guest. Cisco.com is Cisco Systems' primary real-time support channel. Your reseller offers programs that include direct access to Cisco.com services.
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 5400 Series system software and iSCSI driver installation, configuration and usage tips are available on the Cisco Technical Assistance Center (TAC) Web Site.
For example, you can access Cisco SN 5420 "tech tips" by following these instructions:
Step 2 At the Cisco Routers web page, under Cisco SN 5400 Series Storage Routers, click the SN 5420 Product Support link.
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 5400 Series system software and iSCSI drivers.
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Cisco TAC Escalation Center
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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.