NS0-093 Exam Dumps : NetApp Accredited Hardware Support Engineer

In a SAS stack of shelves, the connection between the expander and the disk uses a point-to-point topology.

Point-to-Point:

Each SAS disk in a shelf connects directly to the expander using a dedicated channel. This ensures that communication between the disk and expander is independent of other disks, improving performance and reliability.

Why SAS Uses Point-to-Point:

SAS (Serial Attached SCSI) eliminates the shared bandwidth limitations of traditional bus architectures (e.g., arbitrated loop or ring) by dedicating a connection to each device.

Key Details:

A. arbitrated loop:

Arbitrated loop is a topology used in Fibre Channel systems, not SAS.

C. loop:

SAS does not use loop-based communication; this is typical of older technologies like SCSI Parallel Interface (SPI).

D. ring:

Ring topology is not used in SAS stacks.

Why Other Options Are Incorrect:

"NetApp SAS Shelf and Disk Configuration Guide" specifies point-to-point communication between expanders and disks in SAS environments.

References:

Description:

L1 WDR is a hardware-initiated reset that occurs when the system detects an unrecoverable error or lockup lasting 0.5 seconds.

Key Characteristics:

It performs a hard reset, meaning the system immediately reboots without creating a core dump.

1. L1 Watchdog Reset (WDR):

Description:

L2 WDR is initiated when the system fails to recover from a critical fault after 2 seconds.

Key Characteristics:

It requests a core dump to capture the system state for diagnostic purposes before performing a reset.

2. L2 Watchdog Reset (WDR):

B. L1 WDR is initiated after 0.5 seconds from the event:

This is incorrect because L1 WDR performs a hard reset and does not initiate after 2 seconds.

C. L1 WDR performs a soft reset:

This is incorrect because L1 WDR performs a hard reset, not a soft reset.

Why Other Options Are Incorrect:

"ONTAP Panic Analysis Guide" describes the behavior and timing of L1 and L2 WDR events.

NetApp Support documentation on system resets explains the differences between L1 and L2 watchdog resets.

References:

 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.