NS0-093 NetApp Accredited Hardware Support Engineer Questions and Answers

Reverting to a previous ONTAP version requires careful preparation because ONTAP upgrades often introduce irreversible changes. To successfully revert, the following actions are needed:

C. Reinstall your boot media and install ONTAP 9.5 software

Explanation:You need to reinstall the older version of ONTAP (9.5) on the boot media because the current version (9.7) has been installed as part of the upgrade. The reinstallation ensures that the system boots with ONTAP 9.5.

Steps:

Boot the node into maintenance mode.

Perform the reinstallation using the appropriate ONTAP 9.5 image.

D. Wipe your config and restore from backup

Explanation:A revert requires wiping the configuration because ONTAP upgrades may have made changes to the cluster configuration or WAFL metadata. Restoring the configuration from a backup ensures consistency with the older ONTAP version.

Steps:

Back up the current cluster configuration before proceeding.

Use the restored backup after the revert is complete to reconfigure the system.

Why the Other Options Are Incorrect:

A. Revert from ONTAP 9.7 software to ONTAP 9.6 software and then to ONTAP 9.5 software:

Incorrect. ONTAP reverts must directly target the desired version. You cannot perform multi-step reverts.

B. Delete all Snapshot copies from the past two days:

Incorrect. Deleting Snapshot copies is not a prerequisite for reverting ONTAP. While older Snapshot copies might not be compatible with the reverted version, they do not need to be deleted before the revert.

References:

NetApp Documentation: ONTAP Upgrade and Revert Procedures.

NetApp Knowledge Base: Steps for reinstallation and configuration restoration during a revert.

 Purpose of the diskcopy Command:

The diskcopy command is used in the ONTAP nodeshell environment to perform a low-level sector-by-sector copy of data from one disk to another. This is typically used during data recovery or diagnostics.

 How It Works:

The command copies all sectors from the source disk to the destination disk without any regard for file system or metadata structures.

It is commonly used when replicating the exact state of a failing disk to a spare for further analysis or recovery.

 Key Notes:

The destination disk must be of the same or larger capacity than the source disk.

The operation is typically disruptive and not suitable for production use.

 NetApp Reference Documentation:

Found in the "ONTAP Command Line Manual" for nodeshell utilities. The diskcopy process is highlighted as a low-level disk cloning operation.

To replace a drawer in a DS460c shelf, the following steps must be taken:

Why this is required:Cable chains connect the drawer to the shelf and must be disconnected to safely remove the drawer.

1. Disconnect the cable chains from the chassis

Why this is required:Drives must be removed to avoid damage during the drawer replacement process and to reduce the weight of the drawer for safe handling.

2. Evacuate all drives in the drawer

A. Shut down both nodes:

This is unnecessary because DS460c shelves support online replacement, and the system can remain operational.

C. Power off the shelf:

This is also unnecessary. DS460c shelves are hot-swappable, meaning they do not require the shelf to be powered down.

Why Other Options Are Incorrect:

"DS460c Hardware Service Guide" explains the procedure for replacing a drawer.

NetApp’s "Field Replacement Guide" for DS460c shelves emphasizes online and hot-swappable replacements.

References:

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

How to use:Run the command:

1. CLI (Command Line Interface)python

Copy code

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:

Description:

L1 WDR is a hardware-initiated reset that occurs when the system detects an unrecoverable error or lockup lasting 0.5 seconds.

Key Characteristics:

It performs a hard reset, meaning the system immediately reboots without creating a core dump.

1. L1 Watchdog Reset (WDR):

Description:

L2 WDR is initiated when the system fails to recover from a critical fault after 2 seconds.

Key Characteristics:

It requests a core dump to capture the system state for diagnostic purposes before performing a reset.

2. L2 Watchdog Reset (WDR):

B. L1 WDR is initiated after 0.5 seconds from the event:

This is incorrect because L1 WDR performs a hard reset and does not initiate after 2 seconds.

C. L1 WDR performs a soft reset:

This is incorrect because L1 WDR performs a hard reset, not a soft reset.

Why Other Options Are Incorrect:

"ONTAP Panic Analysis Guide" describes the behavior and timing of L1 and L2 WDR events.

NetApp Support documentation on system resets explains the differences between L1 and L2 watchdog resets.

References:

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

 Explanation of RAID Label Versions:

Disks in ONTAP systems contain metadata known as RAID labels. These labels store critical information such as ownership, aggregate membership, and versioning.

The error indicates a mismatch between the RAID label version on the disk and the supported versions of the ONTAP system.

 Why Option D Is Correct:

If a disk has a RAID label created by a newer version of ONTAP (e.g., version 16) and is then inserted into a system running an older version of ONTAP (e.g., supporting versions 14-15), the label will not be recognized.

This mismatch causes ONTAP to reject the disk.

 Resolution:

Upgrade the ONTAP version to match the RAID label on the disk.

Alternatively, zero the disk to reset its RAID label, but this will erase all data on the disk.

 NetApp Reference Documentation:

The "ONTAP Disk Management Guide" and "ONTAP Compatibility Matrix" explain RAID label versions and compatibility issues when moving disks between ONTAP systems.

To confirm the successful completion of an ONTAP upgrade, the cluster image show-update-progress command provides the necessary details.

Command:

Key Command:cluster image show-update-progress

Displays the status of the cluster upgrade, including which nodes have successfully upgraded and whether the process has completed.

A. system controller sp upgrade show:

This command displays information about SP (Service Processor) firmware upgrades, not ONTAP upgrades.

C. job show –jobtype upgrade:

While this command shows upgrade jobs, it does not confirm the completion of the cluster-wide ONTAP upgrade.

D. system node upgrade-revert upgrade-task –node <nodename> –version <ontap Version>:

This command reverts an upgrade task, not confirms completion.

Why Other Options Are Incorrect:

NetApp "ONTAP Upgrade Guide" specifies the cluster image show-update-progress command as the primary method to verify upgrade completion.

References:

 Possible Causes for "No Disks" Error:

A (Incorrect SAS Cabling): If the SAS cables are incorrectly reconnected or swapped after replacing the boot device, the disks may not be detected because the physical connection to the shelves is compromised. Verifying and reseating the SAS cables is essential.

C (Lower ONTAP Version): If the node boots into an ONTAP version that is lower than the version previously used, it might not recognize the RAID labels or disk metadata created by the higher ONTAP version.

 Why Other Options Are Incorrect:

B (Disks Marked as Failed): Disks that are marked as failed would still be visible in the system, though unusable.

D (Interconnect Down): An interconnect failure affects HA functionality but does not prevent a node from detecting its own disks.

 NetApp Reference Documentation:

Refer to the "ONTAP Boot Recovery Guide" and "SAS Cabling Guide" for steps to resolve disk detection issu

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:

 FRUs on FAS9000 Supporting Replacement Without Takeover:

A (I/O Module): I/O modules can be replaced hot (without takeover) to maintain system uptime during hardware servicing.

D (NVRAM Module): NVRAM modules on FAS9000 can also be replaced without a node takeover, ensuring data integrity during replacement.

 Why Other Options Are Incorrect:

B (DCPM Module): The DCPM (Data Center Power Management) module is not hot-swappable and requires a node takeover.

C (Caching Module): The caching module is integrated and typically requires a node takeover or power-down for replacement.

 NetApp Reference Documentation:

Refer to the "NetApp FAS9000 Hardware Service Guide" for supported FRU replacement procedures and operational constraints.

 Reverting to a Previous ONTAP Version:

Reverting ONTAP software requires specific procedures and is only supported if the ONTAP version being reverted to is compatible with the current cluster configuration.

 Why the Netboot Procedure Is Used:

The netboot process loads the desired ONTAP version directly into memory from a network location and reinitializes the system.

This method is used when a full software revert is required and is often necessary for downgrades to a version that cannot be directly reverted to from the running ONTAP version.

 Key Notes:

A direct revert is not supported from ONTAP 9.7 to ONTAP 9.5 using standard methods due to system metadata changes.

Always verify compatibility using the "ONTAP Software Version Interoperability Matrix".

 NetApp Reference Documentation:

Refer to the "ONTAP Revert/Downgrade Guide" for specific instructions on using the netboot procedure.

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.

If a disk is marked as failed, the Failure Byte on the disk indicates that the disk has been flagged for failure. This can be cleared using the following methods:

What it does:Physically remove the disk from the shelf and reseat it. This action can trigger the system to re-evaluate the disk's status and clear the Failure Byte if the failure was transient or due to connection issues.

1. Reseat the Disk

What it does:Using the disk unfail command in maintenance mode clears the Failure Byte and returns the disk to service.

Command Example:

2. Unfail the Diskdisk unfail

A. Power cycle the disk shelf:

Power cycling the shelf may clear other transient hardware issues but does not specifically clear the Failure Byte.

C. Update the disk firmware:

While updating firmware can prevent future issues, it does not address disks already marked as failed.

Why Other Options Are Incorrect:

NetApp "Disk Maintenance Guide" explains procedures to address failed disks.

The "ONTAP Command Reference" covers the disk unfail command for clearing the Failure Byte.

References:

In a clustered ONTAP system, write requests are acknowledged to the client only after they are securely stored in NVRAM on both the local node and its HA (High Availability) partner.

This ensures redundancy and data protection in case of a node failure.

Write Acknowledgment in NetApp ONTAP:

A. when the write is present in the local node RAM and NVRAM:

Writes are not acknowledged until the HA partner also stores the data in its NVRAM.

B. when the write has been flushed to disk:

Writes are acknowledged before they are written to disk, as NVRAM ensures durability.

D. when the write has been flushed from NVRAM to RAM:

Data is not acknowledged based on RAM; NVRAM on both nodes is the requirement.

Why Other Options Are Incorrect:

NetApp’s "ONTAP Write I/O Processing Guide" explains the role of NVRAM and HA in write acknowledgment.

"Data Protection in ONTAP" highlights the synchronization of NVRAM between HA partners.

References: