Authentic Netapp Certification Exam NS0-093 Questions Answers

Description:

When a negotiated takeover occurs (e.g., for maintenance or upgrades), NVRAM data is replayed by the HA partner to ensure no data is lost.

Relevance:

This ensures that all pending writes are safely processed by the partner node.

1. During a Negotiated Takeover:

Description:

If a node loses power unexpectedly, the HA partner replays the mirrored NVRAM data to protect active write operations.

2. When the Node Loses Power:

A. after triggering a sync core:

Triggering a sync core does not involve NVRAM replay; it captures the system state for debugging.

B. when a node is halted:

Halting a node does not trigger NVRAM replay unless it is part of a negotiated takeover.

Why Other Options Are Incorrect:

"ONTAP High Availability Guide" explains NVRAM mirroring and replay during failover scenarios.

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

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: