NS0-093 NetApp Accredited Hardware Support Engineer Questions and Answers

To analyze the provided panic error, the two sections of AutoSupport that are essential for investigation are:

What it is : HA-RASTRACE.TGZ contains HA (High Availability) system trace logs. It records hardware diagnostics, error traces, and the HA system ' s response to hardware events. These logs are critical when analyzing hardware-related panics, including those caused by PCI errors.

Why it ' s relevant to the panic : In the given panic message, the NMI (Non-Maskable Interrupt) error originates from a Qlogic FC 16G adapter. HA-RASTRACE.TGZ will provide detailed diagnostics, including the error reporting from the HA interconnect and other hardware diagnostics. Specifically, it may include information about how the system detected the PCI fault and any actions taken to protect the system state.

How to analyze :

Extract the HA-RASTRACE.TGZ file from the AutoSupport bundle.

Review hardware-related trace messages for entries associated with the PCI bus or the Qlogic FC adapter.

Look for specific error codes or keywords like PCI Error , NMI , or Qlogic .

References :

NetApp’s " AutoSupport Logs and Diagnostics Guide " highlights HA-RASTRACE.TGZ as a primary resource for debugging hardware faults.

The " Panic Troubleshooting Guide " for ONTAP systems specifies HA-RASTRACE as a key source for identifying NMI-related errors.

1. HA-RASTRACE.TGZ

What it is : SSRAM-LOG records low-level hardware error details, including PCI device register states and uncorrectable memory errors. It is particularly useful for analyzing errors originating in peripheral hardware like network or storage adapters connected via PCI.

Why it ' s relevant to the panic : The panic message explicitly references a PCI Error NMI caused by a Qlogic FC adapter. SSRAM-LOG captures detailed state information for PCI devices, which can help identify whether the fault originated in the adapter hardware, the PCI bus, or another related component.

How to analyze :

Extract the SSRAM-LOG from the AutoSupport bundle.

Search for PCI-related errors, including the specific error source IDs (e.g., ErrSrcID(CorrSrc(0xf00),UCorrSrc(0x18)) ).

Review the log entries to confirm the root cause of the NMI.

References :

The " Hardware Diagnostics and Troubleshooting Guide for ONTAP " lists SSRAM-LOG as a key file for debugging PCI errors.

NetApp’s documentation on PCI diagnostics emphasizes the use of SSRAM-LOG for validating hardware-level faults.

2. SSRAM-LOG

 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 determine the root cause of an unexpected node failure using the Service Processor (SP) , the following commands are helpful:

What it does : Displays recent events logged by the Service Processor. This includes hardware failures, environmental alerts, or other events that may have caused the node failure.

Example Usage :

1. event log show event log show

What it does : Shows information about any core dumps that were generated during the failure. A core dump provides a snapshot of the system state at the time of the failure, which can be analyzed to identify the root cause.

2. system core system core

A. sp status –d :

This command provides status information about the Service Processor itself but does not help diagnose the root cause of the node failure.

C. system log :

This is not a valid Service Processor command.

Why Other Options Are Incorrect:

NetApp " Service Processor Diagnostics Guide " details commands such as event log show and system core for troubleshooting node failures.

References:

To diagnose a PCI/NMI error and collect logs, use the following commands:

What it does : This command collects PCI error logs, including detailed information about PCI devices and the errors that caused the panic.

How to use : Run the command from the nodeshell to capture the required PCI log entries.

1. pelog –a –g=2

What it does : This command reads the SSRAM log file, which contains low-level error information related to PCI and other hardware subsystems.

How to use : Run the command to view the log entries directly for detailed troubleshooting.

2. rdfile /mroot/etc/log/SSRAM

B. show pci –v :

While this command displays PCI device information, it does not provide detailed error logs.

D. event log show :

This displays event log entries but does not contain the specific PCI or NMI-related logs required for diagnosing the panic.

Why Other Options Are Incorrect:

" ONTAP Hardware Troubleshooting Guide " lists pelog and SSRAM as tools for analyzing PCI errors.

" ONTAP Panic Analysis Guide " emphasizes the importance of collecting detailed hardware logs.

References:

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 < node_name >

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.

When a volume is deleted in a NetApp ONTAP system, it is placed in the Volume Recovery Queue . By default, the volume remains in this recovery queue for 12 hours before being permanently deleted. This allows administrators to recover mistakenly deleted volumes within the set retention period.

Explanation of Default Behavior:

Volume Recovery Queue :

This is a feature in NetApp ONTAP that acts as a safety mechanism, providing a grace period for recovering deleted volumes.

The default retention period for volumes in the recovery queue is 12 hours , as confirmed by the NetApp KB: " How to use the Volume Recovery Queue. "

How to Recover a Deleted Volume :

Administrators can recover a deleted volume as long as it remains in the recovery queue and the retention period has not expired.

Use the ONTAP CLI command:

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cluster:: > volume recovery-queue recover -vserver < vserver_name > -volume < volume_name >

This command restores the volume back to its original state.

How to Check the Volume Recovery Queue :

To view volumes in the recovery queue and their expiration times, use:

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cluster:: > volume recovery-queue show

Changing the Default Retention Period :

While the default period is 12 hours , it can be adjusted by administrators to fit specific organizational requirements. This is done via system settings or policies.

Why the Other Options Are Incorrect:

B. 48 hours : Incorrect. The default retention period is not 48 hours; it is 12 hours by default.

C. 72 hours : Incorrect. While a custom configuration could allow this, it is not the default.

D. 24 hours : Incorrect. Although this was previously thought to be the default, NetApp documentation explicitly states it is 12 hours .

References :

NetApp Knowledge Base Article: " How to use the Volume Recovery Queue " .

NetApp ONTAP Documentation: Volume Recovery and Data Management Procedures.

When a node panics in ONTAP, a kernel core file is generated. This core file contains information about the kernel ' s state at the time of the panic and is essential for debugging system crashes.

A kernel core file is produced during a node panic to capture information about the kernel, memory, and processes that led to the crash.

The core file is stored on the root aggregate by default and can be uploaded to NetApp Support using the autosupport invoke-core-upload command.

Key Details:

A. mgwd core :

This is related to the Management Gateway daemon, which handles management traffic. It does not generate a core file during a panic.

B. user space core :

User space cores are generated for processes running in user space, not for kernel panics.

C. sync core :

Sync cores refer to synchronized cores for debugging but are not the primary type generated during a node panic.

Why Other Options Are Incorrect:

" ONTAP Panic Troubleshooting Guide " specifies kernel core files as the output of a node panic.

" ONTAP Core File Management Guide " details the handling of kernel core files after a crash.

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 < aggregate > (replace < aggregate > 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 < aggregate >

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 < 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 < 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 <</b> 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: