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:
* OracleLinux 8 Managing Storage Devices - RAID Configuration
* OracleLinux 8 mdadm Manual
These references provide comprehensive details on RAID levels,mdadmcommand syntax, and options for creating and managing RAID arrays in Oracle Linux.