ATTO Technology 2500C operation manual Performance issues, Checking iPBridge Scsi ports

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Performance issues

If the host is not getting the performance it should, check the following items.

Checking SCSI devices

1Verify that the devices are running at their highest possible SCSI speed. Refer to SCSI configuration commands on page 47.

Mixing SE and LVD devices on the same SCSI bus forces the speed of the bus to SE, thus slowing faster LVD devices. The iPBridge cannot accelerate an already slow device. Refer to Connecting SCSI devices to SCSI ports on page iii of the Appendix.

2Verify that the proper terminator is being used. An SE terminator forces the SCSI bus to SE speeds.

Checking iPBridge SCSI ports

1Verify that the SCSI port configuration is set to the highest speed using the ATTO ExpressNAV interface or CLI. Refer to SCSI configuration commands on page 47.

The iPBridge SCSI port speed, wide negotiation, and sync negotiation settings all affect the speed of the port. By default, these settings are set for optimal speed.

2Verify that the SCSI devices are equally distributed between the SCSI ports. Refer to Alternative interface options on page 33. Optimal performance is seen when only two high-speed SCSI devices are connected to each SCSI port.

Checking iPBridge Ethernet ports

1Verify that the data ports are set to auto negotiate or forced to 1000 Mbs. Refer to Ethernet Port Configuration on page 23.

2Verify that the MTU size is set to optimal setting for the LAN/WAN environment.

Refer to Ethernet Port Configuration on page 23. The current optimized frame size for the iPBridge is 9k. Smaller frame sizes cause a decrease in performance.

3Verify that the iPBridge TraceLog feature is disabled. Tracelog tracks certain events that occur in the iPBridge. With this log enabled, performance suffers.

Refer to Diagnostic commands on page 43.

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Checking the LAN/WAN

1Verify that the MTU size is set to optimal setting for the LAN/WAN environment. Refer to Ethernet Port Configuration on page 23.

9k frame size is the current optimized frame size for the iPBridge. smaller frame sizes cause a decrease in performance. Many switch and router vendors do not support the larger frame size of 9k or 16k.

2Verify that each associated port in the IP SAN is configured for 1000Mbs.

IP SAN traffic should be segmented so that it does not interfere with the main LAN network traffic.For better performance, the IP SAN should be on its own set of hardware.

3Verify that packets are not being dropped along the LAN/WAN. Many utilities track packet activity and switch statistics.

Checking Ethernet Host Adapter or NIC

Ethernet Storage Adapters generally outperform accelerated NICs and un-accelerated NICs by offloading most of the processing from the host.

An accelerated NIC provides some offloading, but still requires a host OS iSCSI driver, making the host spend more CPU cycles.

An un-accelerated NIC does not offload anything so the CPU must do much of the processing.

To check the Ethernet host adapter or NIC

1Verify that the adapter or NIC is sent to auto- negotiate or forced to 1000 Mbs.

2Set the MTU size to the largest MTU size supported in the LAN/WAN. Refer to Ethernet Port Configuration on page 23.

9k frame size is the current optimized frame size for the iPBridge. smaller frame sizes cause a decrease in performance. Many switch and router vendors do not support the larger frame size of 9k or 16k. Set the maximum transfer size to the most efficient size for the intended target(s). For many tape drives, 64k is the optimal setting.

Checking the applications

Some applications can be configured to change transfer sizes. Configure the application for the optimal size for the particular SCSI device(s) connected to the iPBridge.

ATTO Technology Inc. iPBridge Installation and Operation Manual

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Contents Atto iPBridgeTM 2500C/R/D Page Page Contents Additional configurations Copying iPBridge configurationsTroubleshooting Atto ExpressNAV interfaceDiagnostic commands Maintenance commandsAlternative interface options Serial port configuration commands Scsi configuration commandsEthernet commands Ndmp commands ISCSI commandsMapping commands Appendix a Atto iPBridge, FibreBridge familyPage IPBridge 2500 provide storage options IPBridge2500 featuresIntelligent Bridging Architecture, the engine Possible storage Configurations Connectivity, infrastructure solutionsAtto iPBridge 2500R/D Installation instructions LED indicatorsExhibit 1.1-1 Atto iPBridge 2500R/D connector side Serial interfaceBack connector side Atto iPBridge 2500C Operating Temperature 0-70C externalHeight of tallest component .535 inches Exhibit 1.2-1 Atto iPBridge 2500C faceplate Exhibit 1.2-2 Atto iPBridge 2500C board layout Configuring the iPBridge Microsoft iSCSI Initiator changesGetting an IP address Click Launch BrowserNdmp configuration provides backup How Ndmp worksProcedure Setting up NdmpAssign Ndmp names to devices Mapping devices Ndmp Map devices automaticallyMap devices manually Click AutoMapConfiguration mapping Ndmp Mapping devices iSCSI Single Target modeNode names Multiple Target mode Automatically configure Multiple Target modeManually configure Multiple Target mode Click on the Multi Target Mode enabled button Click SubmitMapping single vs. multi target mode Exhibit 2.4-1 Examples of single and multiple target modesExhibit 2.4-2 Mapping with Atto ExpressNAV Additional configurations Change the current user name, passwordCreate a read only password or user name Set the Real Time ClockConfiguring Scsi devices Snmp protocolAccessing ExpressNAV Atto ExpressNAV interfaceBrowser compatibility To optimize ExpressNAV in Internet ExplorerExhibit 3.0-1 An ExpressNAV ExpressNAV pages Restart FirmwareHelp Using Atto ExpressNAV Using FTP over GbEUpdating firmware Preliminary stepsCopying iPBridge configurations Using ZModem over the serial portZModem send clone.cln Send File/ZModem sendTroubleshooting Inside out methodCheck the host event log Check the iPBridge event and trace logsCheck for problems on attached devices Check host versionsComponent check Checking Scsi devicesChecking the iPBridge internal configuration Checking the serial portChecking iPBridge Ethernet ports Checking the LAN/WANChecking the iSCSI Host Adapter or NIC Checking the iSCSI OS driverChecking the Operating System Checking the applicationsChecking iPBridge Scsi ports Performance issuesChecking Ethernet Host Adapter or NIC Checking the host system Alternative interface options Use the serial port or headerUse Telnet Type iPBridge in the New Connection dialog boxExhibit 7.0-1 Start up messages AttoCommand conventions Symbol Indicates CLI provides ASCII-based interfaceCLI commands summary Command Defaults ExampleSntp 38 CLI General use commands Username VerboseModeMaintenance commands SpeedWriteDefault SNTPServerSpeedWrite TimeDiagnostic commands DumpEventLog DumpTraceLogEventLog EventLogFilterPing RouteDisplaySCSIPortList SCSITargetsTemperature SNMPTrapAddressSNMPTraps TailEventLogScsi configuration commands Performance enhancement to newly-mapped Scsi devices VirtualDriveResponseSerialPortBaudRate Serial port configuration commandsSerialPortEcho 50 CLI Ethernet commands 52 CLI Ndmp commands NDMPAuthTypeNDMPMaxVersion NDMPPortNumber54 CLI ISCSI commands ISNSServer ISNSLoginControlMultiTargetMode AutoMap Mapping commandsRoute List to the map which satisfies a search for the given LUN Appendix a Atto iPBridge, FibreBridge family Product features 2500C/R/D 2700C/R/D 1500E/D 1550E/DIPBridge products Fibre Bridge products Appendix B Cabling Scsi cablingCable types ExamplesEthernet connections Appendix C Glossary Term DefinitionVi Appendix Appendix D Safety standards and compliances FCC Standards Radio and Television InterferenceEuropean Standards Appendix E Atto accessories Appendix F Warranty, contact information Contact Atto Technology, Inc
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