NetApp NS0-093 NetApp Accredited Hardware Support Engineer Exam Practice Test

Answer : A

Functionality of RAID Error Propagation (REP):

RAID Error Propagation (REP) ensures that errors on the disk layer, such as unrecoverable read errors, do not propagate as inconsistencies into the WAFL (Write Anywhere File Layout) metadata layer.

WAFL is designed to manage data blocks, and if an error occurs on a user data block, WAFL can identify and handle it gracefully without flagging an inconsistency.

Why Option A Is Correct:

REP ensures that errors on a user data block are isolated and do not trigger WAFL inconsistencies. Instead, the error is handled at the RAID layer or higher without corrupting metadata.

This design provides a robust mechanism to protect against data integrity issues caused by disk errors.

NetApp Reference Documentation:

Refer to the 'ONTAP Storage Management Guide' and the 'NetApp RAID Guide,' which explain how RAID and WAFL interoperate and how REP is implemented.

Answer : A, C

Understanding a Single PHY Down Issue:

In SAS environments, a PHY represents a physical layer connection between devices.

When a single PHY reports a 'down' status, it typically indicates an issue with the physical connectivity or the associated hardware.

Cause 1: Improperly Seated Cable

If the SAS cable is not properly seated in the port, the connection for one or more PHYs may fail.

Reseating the cable on both ends (controller and shelf) often resolves the issue.

Cause 2: Defective Cable

A damaged or faulty SAS cable can cause PHY errors.

Replacing the cable and verifying the connection resolves the issue in this case.

Why Other Options Are Not Likely:

B . Outdated IOM firmware: While outdated firmware can cause other issues, it rarely affects only a single PHY.

D . Offline shelf: If an entire shelf is offline, more than one PHY would typically be affected, as multiple connections are involved in SAS stacks.

NetApp Reference Documentation:

Found in the 'ONTAP SAS Cabling Guide' and 'Shelf Troubleshooting Guide'. These documents detail troubleshooting for PHY errors and common SAS hardware issues.

Answer : B, C

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 <disk> 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 <disk> 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.

Answer : A

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.

Answer : B

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.

Answer : C, D

To trigger an AutoSupport message in ONTAP, the following commands are valid:

1. ::> autosupport invoke --node <nodename> --type all

What it does: This command manually triggers a complete AutoSupport message of type 'all.' This includes logs and system information from all subsystems.

How to use:

Run the command: autosupport invoke --node <nodename> --type all

Replace <nodename> with the name of the node for which you want to generate the AutoSupport message.

Why it's relevant: This is the primary method for triggering a full AutoSupport message manually. It is commonly used during troubleshooting to provide comprehensive system data to NetApp Support.

2. ::> autosupport invoke-core-upload --node <nodename>

What it does: This command is specifically used to upload core files (e.g., kernel or user space cores) from a node to NetApp Support for analysis.

How to use:

Run the command: autosupport invoke-core-upload --node <nodename>.

Replace <nodename> with the name of the node for which you want to upload core files.

Why it's relevant: If there is a system panic or other critical issue, this command ensures that core files are included in the AutoSupport message for detailed analysis.

Why Other Options Are Incorrect:

A . ::> autosupport history show-upload-details --node <nodename>:

This command displays the history of AutoSupport uploads but does not trigger a new AutoSupport.

B . ::> system node coredump upload --node <nodename>:

This command uploads coredumps directly to a support server but does not trigger an AutoSupport message.

'ONTAP 9 AutoSupport Configuration Guide' confirms autosupport invoke as a valid command to trigger AutoSupport messages.

'ONTAP CLI Reference Manual' specifies autosupport invoke-core-upload for core file uploads.

Answer : C

To collect shelf logs for a DS4246 shelf in an ONTAP 9.12.1 system, you must invoke a diagnostic AutoSupport specifically targeting the storage subsystem. This action ensures that detailed storage logs, including shelf logs, are included in the AutoSupport bundle.

Steps to Collect Shelf Logs:

Use the following command:

bash

Copy code

system node autosupport invoke -node <node_name> -type diagnostic -subsystem storage

Replace <node_name> with the name of the node experiencing the issue.

This command generates an AutoSupport message that includes logs related to storage subsystems, such as disk shelves and adapters.

Provide the AutoSupport case number to NetApp Support for further analysis.

Why Other Options Are Incorrect:

A . Provide the output of the nodeshell command rdfile /etc/log/shelflog:

While this command allows manual reading of shelf logs, it is not a recommended or comprehensive approach for collecting logs for NetApp Support cases.

B . Invoke an AutoSupport of type all using Active IQ Unified Manager:

This action generates a generic AutoSupport bundle, which may not include detailed shelf logs unless explicitly targeted.

D . Invoke a diagnostic AutoSupport with the subsystem log_files:

The log_files subsystem targets general system logs, not storage-specific logs like shelf logs.

'ONTAP 9 AutoSupport and Diagnostics Guide' outlines the use of the subsystem storage option for collecting shelf logs.

The 'Troubleshooting Storage Subsystems' documentation specifies diagnostic AutoSupport as the method for gathering shelf-related logs.