NS0-093 NetApp Accredited Hardware Support Engineer Questions and Answers

When using wafliron to repair WAFL inconsistencies on an aggregate, the aggregate becomes available after Phase 4 of the wafliron process is complete.

Phase 1: Initial scan to identify inconsistencies.

Phase 2: Corrects directory and inode structure issues.

Phase 3: Repairs blocks and metadata.

Phase 4: Completes final repairs and verification, after which the aggregate can be made available.

Phases of wafliron:

A. when the administrator manually onlines the aggregate:

The aggregate cannot be manually brought online until wafliron completes Phase 4.

B. when wafliron is started:

Starting wafliron does not make the aggregate available; repairs need to be completed first.

D. after the mounting phase of wafliron is complete:

WAFLiron does not have a specific "mounting phase." Mounting happens after Phase 4 completes.

Why Other Options Are Incorrect:

"NetApp WAFLiron Troubleshooting Guide" explains the availability of the aggregate after Phase 4.

NetApp Support documentation outlines the phases of wafliron and aggregate recovery.

References:

To troubleshoot the root cause of an unexpected controller reboot, the following tools are commonly used:

What it does:Provides monitoring and performance data for the ONTAP cluster, including historical event logs that may help identify the root cause of a reboot.

1. Active IQ Unified Manager

What it does:The CLI allows you to gather logs and status information directly from the affected node. Commands like event log show and system core are essential for identifying the reason behind the reboot.

2. ONTAP CLI

B. Active IQ Digital Advisor:

This tool focuses on predictive analytics and proactive recommendations, not troubleshooting unexpected reboots.

D. ONTAP Mediator:

This tool is used for managing MetroCluster configurations, not for troubleshooting reboots.

E. Active IQ Config Advisor:

This tool checks for configuration best practices but does not provide detailed logs or reboot diagnostics.

Why Other Options Are Incorrect:

NetApp "ONTAP System Management Guide" emphasizes the use of Unified Manager and CLI for troubleshooting system issues.

References:

When a WAFL inconsistency is detected, the first step is to stabilize the system before attempting any repairs or recovery.

Stabilize the System:

Ensure that the system is not experiencing ongoing hardware or software issues.

Avoid making changes to the affected aggregate or volume until the system is stable.

Assess the Impact:

Determine which aggregates or volumes are affected and the severity of the inconsistency.

Steps to Handle WAFL Inconsistency:

A. Run wafliron:

Running wafliron should only be done after stabilizing the system and under guidance from NetApp Support.

C. Force offline the affected aggregate:

Forcing an aggregate offline without proper assessment can lead to data loss.

D. Run a dump to null:

Dumping data is not relevant for resolving a WAFL inconsistency.

Why Other Options Are Incorrect:

"NetApp WAFL Troubleshooting Guide" specifies that stabilization is the first step after detecting inconsistencies.

NetApp Support documentation provides guidelines for handling WAFL inconsistencies safely.

References:

 Options for Uploading Core Files:

Core files are diagnostic dumps created during system failures for analysis by NetApp Support.

They can be uploaded via multiple methods, depending on system configuration and access:

 Option B (CIFS Download):

Core files can be downloaded from the node using a CIFS share and then manually uploaded to upload.netapp.com.

This method is useful if automated processes are unavailable or connectivity is limited.

 Option D (Autosupport Invoke-Core-Upload):

The command system node autosupport invoke-core-upload automates the process of uploading the core file to NetApp.

It uses the configured Autosupport mechanism to transfer the file to NetApp Support for analysis.

 NetApp Reference Documentation:

"ONTAP Autosupport Guide" and "ONTAP Troubleshooting Guide" provide instructions for manually and automatically uploading core files.

 Best Practices for SAS Cabling in AFF A700 Systems:

The AFF A700 system has built-in SAS ports (e.g., 2a and 2b) as well as additional SAS ports on optional SAS cards.

To ensure high availability and redundancy, it is recommended to distribute SAS connections across multiple SAS ports from different controllers or slots.

 Why Port 2a and 9a Are Recommended:

Port 2a is a built-in SAS port on the AFF A700 system.

Port 9a belongs to the additional SAS card in slot 9.

By connecting the stack using 2a and 9a, you utilize different SAS domains (built-in controller ports and add-on card ports), providing both path redundancy and load balancing.

 NetApp Reference Documentation:

"NetApp Hardware Universe" and "ONTAP Hardware Installation Guide" highlight that SAS cabling for redundancy should leverage different ports, including those from separate SAS controllers or add-on cards.

NetApp's best practice guidelines suggest avoiding connections to the same SAS controller or port group for critical stacks.

When a node fails to boot and loads the previous version of ONTAP, it usually indicates that the primary boot location is incorrect. To resolve this:

Enter the LOADER Prompt:

Interrupt the boot process to access the LOADER prompt.

Set the Primary Kernel URL:

Use the following command:

Steps to Boot the Correct ONTAP Version:setenv GX_PRIMARY_KERNEL_URL

Boot the Node:

Run the boot command to load the correct version.

B. From the loader prompt of nodeA1, run boot_backup:

Booting the backup image may result in an outdated version of ONTAP, not the desired version.

C. From the clustershell of the partner, run system node image modify:

Modifications to the ONTAP image must be done from the LOADER prompt, not the clustershell.

D. From the clustershell of nodeA1, run system node image modify:

NodeA1 cannot load ONTAP, so this command cannot be run.

Why Other Options Are Incorrect:

"ONTAP System Boot Guide" explains how to resolve boot issues using the LOADER prompt.

NetApp documentation on environment variables includes the use of GX_PRIMARY_KERNEL_URL.

References:

In a SAS stack of shelves, the connection between the expander and the disk uses a point-to-point topology.

Point-to-Point:

Each SAS disk in a shelf connects directly to the expander using a dedicated channel. This ensures that communication between the disk and expander is independent of other disks, improving performance and reliability.

Why SAS Uses Point-to-Point:

SAS (Serial Attached SCSI) eliminates the shared bandwidth limitations of traditional bus architectures (e.g., arbitrated loop or ring) by dedicating a connection to each device.

Key Details:

A. arbitrated loop:

Arbitrated loop is a topology used in Fibre Channel systems, not SAS.

C. loop:

SAS does not use loop-based communication; this is typical of older technologies like SCSI Parallel Interface (SPI).

D. ring:

Ring topology is not used in SAS stacks.

Why Other Options Are Incorrect:

"NetApp SAS Shelf and Disk Configuration Guide" specifies point-to-point communication between expanders and disks in SAS environments.

References:

 Steps to Unfail a Disk in Maintenance Mode:

When a disk is marked as "failed," it is added to the Failed Disk Registry and marked as unusable by the system. Unfailing a disk involves removing it from this registry and resetting its state.

 Step 1: Remove the Disk from the Failed Disk Registry

Use the command: registry remove to delete the disk from the Failed Disk Registry. This clears its "failed" status.

 Step 2: Use the Disk Unfail Command

Execute the disk unfail command to reset the disk status and make it available for use.

 Key Notes:

After unfailing, the disk will be treated as a spare and must be reassigned or re-added to an aggregate.

If the disk remains failed after these steps, physical hardware issues may need to be addressed.

 NetApp Reference Documentation:

The "ONTAP Maintenance Mode Guide" and "Disk Management Guide" provide detailed instructions for handling failed disks and using the disk unfail command.

In a NetApp high-availability (HA) configuration, multipath HA ensures redundancy by providing two independent paths from each controller to the connected storage. If the system is currently showing Single-Path HA, it means only one path is operational or connected, which is a potential single point of failure.

To convert the configuration to multipath HA, additional cabling must be configured to establish the second path. For the AFF A220 system, the correct connections are as follows:

Explanation of the Correct Answer:

AFF A220 Port Configuration for HA:

Each controller in an AFF A220 has ports labeled 0a, 0b, 0c, and 0d for connectivity.

In a multipath HA configuration, each controller must have two independent paths to the connected storage via the partner controller's disk shelves.

Correct Cabling for Multipath HA:

Port 0a on both controllers must be connected to the corresponding port (e.g., disk shelf stack or Inter-Switch Link).

Port 0c on both controllers must also be connected to complete the redundant path.

These connections ensure that there are two independent data paths between the controllers and the storage system, providing fault tolerance in case one path fails.

Single-Path HA to Multipath HA:

If the system currently shows Single-Path HA, it is likely that only one set of ports (e.g., 0a and 0b) are cabled.

Adding the additional connections on 0a and 0c establishes the second path required for multipath HA.

Why the Other Options Are Incorrect:

A. 0a and 0b on both controllers should be connected:

This option only connects ports 0a and 0b, which does not establish a multipath HA configuration. Port 0c is also required for redundancy.

C. 0c and 0d on both controllers should be connected:

Connecting only 0c and 0d would leave ports 0a disconnected, failing to establish a proper multipath HA setup. Both 0a and 0c are required.

D. 0a and 0d on both controllers should be connected:

Connecting 0a and 0d is not the standard configuration for multipath HA in an AFF A220 system. Port 0c is part of the required configuration.

How to Verify the Configuration:

Use the following ONTAP command to verify the HA status:

cluster::> storage failover show -fields multipath-ha

This will display whether the system is in multipath HA or single-path HA mode.

Check the port connectivity:

cluster::> network port show -node

References:

NetApp Hardware Installation and Setup Guide for AFF A220.

NetApp Knowledge Base: "Configuring Multipath HA for AFF Systems."

ONTAP 9.x System Administration Guide: "High Availability Configurations."

 Understanding Single-Path HA vs. Multipath HA:

Single-Path HA indicates that only one path exists between the controllers and the connected shelves, leading to limited redundancy.

Multipath HA requires both controllers to have redundant SAS connections to the shelves.

 Cabling for Multipath HA in AFF A220 Systems:

To achieve multipath HA, you must connect 0c and 0d on both controllers to the appropriate stack ports on the shelves.

This ensures dual paths for each controller to access the storage shelves.

 NetApp Reference Documentation:

Refer to the "ONTAP Multipath HA Configuration Guide" and the "NetApp Hardware Installation Guide" for AFF A220 systems for cabling diagrams and best practices.

To ensure that POST (Power-On Self-Test) runs on boot, the setenv POST=true command is used at the LOADER prompt. This command enables the system to perform POST diagnostics before proceeding with the boot process.

POST Purpose: POST checks system hardware components (such as memory, disk, and controllers) for faults before loading the ONTAP kernel.

How to Use:

At the LOADER prompt, type:

Key Details:arduino

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setenv POST=true

Save the configuration and reboot the system.

B. bye:

This command restarts the system but does not ensure that POST runs on boot.

C. boot_diag:

This command boots the system into diagnostic mode but is not directly related to enabling POST on boot.

D. boot_ontap:

This command boots ONTAP but skips POST if it is not explicitly enabled.

Why Other Options Are Incorrect:

NetApp "ONTAP System Boot and Recovery Guide" describes setenv POST=true for enabling POST diagnostics.

References:

 Upgrade Considerations for Disk and CPU Utilization:

During an ONTAP upgrade, it is critical to ensure the system has sufficient resources to handle the upgrade process without impacting normal operations.

 Recommended Threshold:

NetApp recommends that both disk and CPU utilization should be below 70% before initiating an upgrade. This ensures that there is enough headroom for the upgrade operations and avoids performance degradation.

 Steps to Verify Utilization:

Use the system node show -fields cpu command to check CPU usage.

Use the storage aggregate show -fields used command to check aggregate disk utilization.

 NetApp Reference Documentation:

"ONTAP Upgrade and Maintenance Guide" specifies the 70% threshold for disk and CPU usage during upgrade planning.

The "ONTAP Performance Management Guide" provides methods for monitoring system resource utilization.

To invoke AutoSupport in ONTAP, the following tools can be used:

How to use:Run the command:

1. CLI (Command Line Interface)python

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autosupport invoke -node -type all

This triggers AutoSupport to collect and send logs and system information.

How to use:Log in to the Active IQ portal and use its interface to request an AutoSupport message from the connected ONTAP systems.

2. NetApp Active IQ website

A. NetApp Cloud Insights:

This tool is used for monitoring and performance analysis, not for triggering AutoSupport messages.

D. the SmartSolve tool:

SmartSolve is used for case resolution guidance but does not invoke AutoSupport.

Why Other Options Are Incorrect:

"ONTAP AutoSupport Guide" provides instructions for invoking AutoSupport via CLI and Active IQ.

References:

In maintenance mode, the command disk show –v provides detailed information about disk ownership. This includes the current owner, previous owner, and disk health status.

Enter maintenance mode, and run:

How to Use:disk show –v

The output will display ownership information for each disk, including its RAID group and current assignment.

A. sysconfig –v:

This command provides system configuration details but does not show disk ownership.

C. aggr status:

This command shows the status of aggregates, not individual disks or their ownership.

D. storage show disk –p:

This command is not valid in maintenance mode.

Why Other Options Are Incorrect:

NetApp "Maintenance Mode Commands Guide" highlights disk show –v as the command to check disk ownership.

References:

To determine whether an aggregate is WAFL (Write Anywhere File Layout) inconsistent, the following two commands can be used:

What it does:This command directly checks the WAFL consistency status of the specified aggregate. If an aggregate is WAFL inconsistent, it will report the inconsistency in the output.

How to use:

Run the command: wafiron show (replace with the name of the aggregate).

Look for indications of WAFL inconsistency in the output.

Why it's relevant:The wafiron utility is specifically designed to provide WAFL status and diagnostics. It is the most accurate and direct way to confirm whether an aggregate is inconsistent.

References:

"WAFL Troubleshooting Guide" from NetApp highlights the wafiron show command as a primary tool for checking aggregate consistency.

1. wafiron show

What it does:This command displays RAID information for all aggregates on the specified node. If an aggregate is WAFL inconsistent, it will be explicitly mentioned in the output.

How to use:

Run the command: node run –node sysconfig –r.

Check the output for the phrase "WAFL inconsistent" under the corresponding aggregate.

Why it's relevant:This command provides additional context, such as the RAID group details, which can help understand whether the inconsistency is isolated or part of a larger issue.

References:

"ONTAP CLI Commands Guide" specifies sysconfig –r as a method to verify aggregate status, including WAFL consistency.

2. node run –node sysconfig –r

C. storage aggregate show:

This command displays aggregate configuration and usage information but does not report WAFL inconsistency.

D. node run –node <node> sysconfig –a:

While this command shows detailed hardware configuration information, it does not include WAFL consistency status for aggregates.

Why Other Options Are Incorrect:

 Command Syntax for Downloading ONTAP Image:

The cluster image package get command is used to download the ONTAP image from a specified URL to the cluster's image repository.

The syntax requires the –url parameter followed by the full URL of the image file.

 Why Option C Is Correct:

This command syntax directly downloads the image from the local web server at http://192.168.10.10/ to the ONTAP cluster repository.

Other options either refer to incorrect commands or unsupported URLs.

 NetApp Reference Documentation:

The "ONTAP Software Upgrade Guide" provides the exact command and steps for downloading ONTAP images via HTTP or FTP.