NS0-093 Exam Dumps - Netapp NAHSE Questions and Answers

 What Is a Watchdog Timeout?

The watchdog is a software or hardware mechanism that monitors the system’s health and ensures it is operating correctly.

If the system fails to respond or update the watchdog timer within the specified time, the watchdog triggers a system panic to avoid further corruption or damage.

 Cause of Watchdog Timeout:

This usually occurs due to:

A hardware failure (e.g., CPU or memory issue).

A software bug causing a system hang or crash.

The panic ensures the system stops operation to preserve data integrity and aid in troubleshooting.

 NetApp Reference Documentation:

"ONTAP Troubleshooting Guide" and "Core Dump Analysis Guide" provide details on interpreting watchdog timeouts and recommended actions.

To manually generate a kernel core file in ONTAP, the following commands can be used:

What it does:Reboots the specified node and generates a core dump before rebooting.

Example Usage:

1. ::> reboot –node –dump truereboot –node –dump true

What it does:Halts the specified node and generates a core dump before shutting down.

Example Usage:

2. ::> halt –dump true –node halt –dump true –node

What it does:Forces a panic on the specified node, which triggers a kernel core dump.

Example Usage:

3. ::> system node panic –node system node panic –node

A. SP> system power cycle:

This command reboots the system from the Service Processor but does not generate a core dump.

E. SP> system core:

This command displays core file information but does not generate a new core dump.

Why Other Options Are Incorrect:

NetApp "Kernel Core Dump Guide" explains the use of reboot, halt, and panic commands to trigger core dumps.

ONTAP CLI Reference includes the syntax for these commands.

References:

A NetApp WAFL (Write Anywhere File Layout) inconsistency in a RAID-DP aggregate could occur in the following scenarios:

Why this causes inconsistency:

RAID-DP is designed to handle up to two concurrent disk failures. However, if a block error occurs during the reconstruction process (e.g., unreadable data on the surviving disks), the RAID group cannot rebuild the lost data, leading to WAFL inconsistencies.

1. Two disks failing and a block error during reconstruction

Why this causes inconsistency:

If two disks in the same RAID group fail nearly simultaneously (before the RAID-DP can reconstruct data from the first failed disk), the system cannot recover the data, resulting in WAFL inconsistencies.

2. Two disks failing within seconds of each other

B. rebooting a node during a disk reconstruction:

Rebooting a node does not cause WAFL inconsistency because ONTAP ensures that RAID reconstructions resume upon reboot without data loss.

D. both party disks failing:

This is not a valid RAID-DP term.

Why Other Options Are Incorrect:

"WAFL and RAID-DP Operations Guide" explains failure scenarios that could cause inconsistencies.

NetApp's "Troubleshooting RAID Groups and Aggregates" covers recovery procedures for double-disk failures and reconstruction errors.

References:

When ONTAP detects a WAFL inconsistency in an aggregate, it automatically generates an AutoSupport message with the description WAFL INCONSISTENT BLOCK.

WAFL INCONSISTENT BLOCK:

This error indicates that WAFL metadata or user data blocks have been found to be inconsistent.

ONTAP triggers an automatic AutoSupport message to notify administrators and NetApp Support.

Key Details:

A. MEDIUM ERROR DURING RECONSTRUCTION:

This error occurs during disk reconstruction, not due to WAFL inconsistencies.

B. CHECKSUM ERROR:

A checksum error indicates a disk-level data integrity issue, not a WAFL inconsistency.

C. WAFL INCONSISTENT USER DATA BLOCK:

While related, this is not the specific AutoSupport message triggered by ONTAP.

Why Other Options Are Incorrect:

NetApp "ONTAP WAFL Troubleshooting Guide" describes AutoSupport messages related to WAFL inconsistencies.

References:

 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.

The following ONTAP systems support both SSD and SAS disks:

Description:

The FAS2750 is part of NetApp's hybrid storage array product line.

It supports both SSDs for performance tiers and SAS disks for capacity tiers, making it suitable for mixed workloads.

1. FAS2750

Description:

The FAS8200 is an enterprise-level storage system that also supports hybrid configurations with both SSD and SAS drives.

This system is designed to handle high performance and capacity needs.

2. FAS8200

A. AFF C190:

The AFF C190 is an all-flash system and only supports SSDs. It does not support SAS disks.

C. AFF A220:

Like the AFF C190, the AFF A220 is also an all-flash system that supports SSDs only.

Why Other Options Are Incorrect:

NetApp "Hardware Universe" confirms drive support for FAS and AFF systems.

NetApp product documentation details supported disk types for hybrid and all-flash systems.

References:

If a node is not booting, the following methods can be used to access the system for troubleshooting:

What it does:The SP provides out-of-band management access to the node, even if the node is not booting.

How to use:

Connect to the SP using SSH or a direct console connection.

Use SP commands to gather logs or perform diagnostics.

1. Service Processor (SP)

What it does:The serial console provides direct access to the node's bootloader or maintenance mode.

How to use:

Connect to the serial port using a terminal emulator.

Use console commands to interact with the system.

2. Serial Console

A. node management port:

The node management interface is only accessible if the node is booted and ONTAP is running.

B. cluster management port:

The cluster management interface requires the cluster to be operational, which is not possible if the node is not booting.

Why Other Options Are Incorrect:

NetApp "Service Processor and Serial Console Guide" provides instructions for accessing a non-booting node.

References:

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: