9.5 Chapter Summary

Simple Problem-Isolation Techniques

• Most SAN connectivity problems occur during an add, move, or change to the storage network.

• The presence of optical signaling can be verified at cable ends of both nodes and switch ports.

• Adapter cards should be verified for appropriate microcode and device driver versions.

• Vendors may require specific addresses or address ranges for proper adapter configuration.

• Successful connection to the fabric can be verified by examination of the SNS or iSNS table entries.

• Improper zoning or LUN masking settings may inadvertently prevent an initiator from discovering an authorized storage target.

• In multiswitch fabrics, E_Port compatibility modes and principal switch priority should be verified to ensure interoperability.

• Storage targets may have LUN and LUN masking configuration utilities that should be harmonized with similar utilities in adapters or switches.

Fibre Channel Analyzers

• Data capture typically takes only several seconds and may be triggered by specific protocol or frame conditions.

• Capture may be performed against one or two ports concurrently.

• Analyzers may include frame and error injection utilities.

• Analyzers may provide point-in-time performance monitoring.

iSCSI Network Analyzers

• iSCSI network analyzers provide both link and network layer protocol decode.

• iSCSI PDUs are decoded to provide analysis of storage transactions in addition to TCP/IP transport.

• iSCSI network analyzers may also provide point-in-time link utilization statistics.

Performance Tools

• Performance monitoring over time provides a comprehensive view of SAN traffic and periods of peak activity.

• Performance statistics are solicited from SAN network equipment and compiled into a database.

• Performance monitoring may indicate trends in SAN utilization over a period of days, weeks, or months.

• Performance monitoring is useful for verifying service level agreements.