Which mdadm command creates a RAID-1 device consisting of two block volumes and one spare...

The correct command to create a RAID-1 device (mirroring) consisting of two block volumes with one spare device is optionC:mdadm –create /dev/md0 –level=1 –raid-devices=2 /dev/xvdd1 /dev/xvdd2 –spare-devices=1 /dev/xvdd3.

RAID Level 1:RAID-1, also known as mirroring, involves creating an exact copy (or mirror) of a set of data on two or more disks. This ensures data redundancy; if one disk fails, the other can still provide the data.

mdadm Command Structure:Themdadmcommand is used to manage and monitor RAID devices on Linux. To create a new RAID array, the--createoption is used, followed by several parameters:

/dev/md0: The name of the RAID device to be created.

--level=1: Specifies RAID level 1 (mirroring).

--raid-devices=2: Indicates the number of active devices (two in this case) to be used in the RAID array.

/dev/xvdd1 /dev/xvdd2: The two block devices that will form the RAID-1 array.

--spare-devices=1 /dev/xvdd3: Specifies one spare device (/dev/xvdd3). A spare device is used to automatically replace a failed device in the RAID array.

Option Analysis:

A.Incorrect because it specifies RAID level 5 (--level=5), which requires at least three devices and does not match the requirement for RAID-1.

B.Incorrect because it does not include the--spare-devices=1option, meaning there is no spare device included in this configuration.

C.Correct as it specifies RAID-1 (--level=1), two active devices (--raid-devices=2), and one spare device (--spare-devices=1).

D.Incorrect because it specifies RAID level 0 (--level=0), which is a striped set (no redundancy), not a mirrored set (RAID-1).

Oracle Linux Reference:For more detailed information aboutmdadmand RAID configurations in Oracle Linux 8, refer to the following Oracle Linux documentation:

Oracle® Linux 8 Managing Storage Devices - RAID Configuration

Oracle® Linux 8 mdadm Manual

These references provide comprehensive details on RAID levels,mdadmcommand syntax, and options for creating and managing RAID arrays in Oracle Linux.