NetApp NS0-093 Exam - Topic 1 Question 22 Discussion

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

1. Two disks failing and a block error during reconstruction

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.

2. Two disks failing within seconds of each other

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.

Why Other Options Are Incorrect:

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.

'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.