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 Outdated IOM firmware: While outdated firmware can cause other issues, it rarely affects only a single PHY.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

Write Acknowledgment in NetApp ONTAP:

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.

Why Other Options Are Incorrect:

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.

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.

Answer : B, C

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

1. CLI (Command Line Interface)

How to use: Run the command:

python

Copy code

autosupport invoke -node <nodename> -type all

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

2. NetApp Active IQ website

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

Why Other Options Are Incorrect:

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.

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