NetApp NS0-093 Exam Questions

To determine whether an aggregate is WAFL (Write Anywhere File Layout) inconsistent, the following two commands can be used:

1. wafiron show

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.

'WAFL Troubleshooting Guide' from NetApp highlights the wafiron show command as a primary tool for checking aggregate consistency.

2. node run --node <node> sysconfig --r

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.

'ONTAP CLI Commands Guide' specifies sysconfig --r as a method to verify aggregate status, including WAFL consistency.

Why Other Options Are Incorrect:

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.

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.

To recover an inconsistent aggregate, the following tools can be used:

1. wafl_check

What it does: This tool is used to perform a consistency check on WAFL metadata. It identifies and attempts to fix WAFL inconsistencies in aggregates.

When to use: Run wafl_check after identifying WAFL inconsistencies to repair minor metadata issues.

2. wafliron

What it does: This tool repairs WAFL inconsistencies by reconstructing metadata. It is more powerful than wafl_check and should only be run under NetApp Support guidance, as improper use can result in data loss.

When to use: Use wafliron for severe WAFL inconsistencies that cannot be resolved by wafl_check.

Why Other Options Are Incorrect:

A . file check:

This is not a valid NetApp tool.

C . wafl snapiron:

While similar in name, snapiron is used for snapshot recovery, not aggregate recovery.

'ONTAP Aggregate Troubleshooting Guide' details the usage of wafl_check and wafliron.

NetApp Support documentation provides guidelines for recovering inconsistent aggregates.

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.

A . NVMEM battery

Explanation: The NVMEM (Non-Volatile Memory) battery is a critical component for retaining data in case of a power failure. It is classified as a Field Replaceable Unit (FRU) in an AFF A220 system.

Replacement Notes:

Replacement can be performed by field engineers.

The system will typically alert you when the battery requires replacement.

B . mSATA boot device

Explanation: The mSATA (mini-SATA) boot device contains the ONTAP operating system and is also a FRU in the AFF A220. It is critical for the system's boot process and can be replaced if it becomes faulty.

Replacement Notes:

Boot devices are easily replaceable while ensuring ONTAP is reinstalled on the new device.

Why the Other Options Are Incorrect:

C . NVMe Flash Cache feature:

Incorrect. NVMe Flash Cache is not a physical FRU but a feature for accelerating read performance. It is implemented via software and NVMe-based SSDs, which are not specifically field replaceable in AFF A220.

D . Chassis fan:

Incorrect. The AFF A220 does not classify chassis fans as FRUs. These are usually part of the cooling system, but their replacement may require system shutdown or is integrated into the design.

NetApp Hardware Documentation: AFF A220 Component Replacement Guide.

NetApp Knowledge Base: Articles on replacing NVMEM batteries and mSATA boot devices.