Emulex Adapters - Manual (Page 8)

Troubleshooting and Maintenance Manual Page 5
• Old cables. 4Gb/s FC cannot run as far as 2Gb/s FC with the same cable.
• Switch
• Improper zoning. This causes devices to be improperly discovered and the SAN does
not recover from disturbances.
• Link problems. These include wrong speed, wrong topology or no link at all.
• Storage
• Improperly configured storage systems. Emulex has determined that this is the number
one cause of SAN performance problems. Examples of improperly configured storage
systems include not enough spindles dedicated to the busiest logical unit numbers
(LUNs) or too many hosts talking to a particular storage port.
Server Components
Server problems can include the adapter and its firmware, adapter device drivers, adapter management
software, OS SCSI stack drivers and path management software.
• Adapter firmware
• Unqualified firmware. If the firmware is not qualified by the storage and systems provid-
ers, unpredictable behaviors could result.
• Outdated firmware. Outdated firmware can cause link problems (wrong speed, wrong
topology or no link at all). Tape backups can fail when using the FCP-2 Sequence Level
Recovery feature, which is enabled automatically if the tape system supports it.
• Unsupported dual-channel adapters. Some dual-channel adapters are not supported by
certain systems.
• Bad adapters. If the system stops responding, install the adapter in another server to
determine if the problem is the adapter.
• Adapter device drivers
• Unqualified driver version. The version must be qualified by the storage and systems
providers. A version can be installed and supported by the storage or system provider,
but provider compatibility specifies an older driver version is required for a particular
configuration.
• Incorrectly set configuration parameters. If the driver parameters are set incorrectly,
erratic behavior can occur such as very long failure timeouts, storage being overrun by
too many concurrent commands and failures in path management software that rely on
specific Emulex driver settings.
• Incorrect target binding. If persistent binding is not correct, devices that are expected to
show in the OS storage management tool are not present.
• Adapter management software
• Management software package does not match the driver version. If the package does
not match the driver version, erratic behavior can occur with the management standard
HBA API, firmware downloads and functions of the OneConnect Manager and HBAny-
ware application. For best results, use the OneConnect Manager or HBAnyware utility
version that is packaged with the driver.
• OS SCSI stack drivers
• Wrong OS patch level. An incorrect level can affect system performance. OS providers
often patch elements of the SCSI stack to correct problems and improve performance.
OS providers generally maintain a knowledgebase, search there if you are experiencing
a problem. OS patches can require coordinated changes in low-level device drivers from
the adapter makers to work properly. For example, Emulex specifies (on the Emulex