LCA File Systems & Storage Management 3

Question 1

Which command checks and repairs an XFS filesystem that is NOT currently mounted?

Accepted Answer

xfs_repair /dev/sdc1

Answer

xfs_repair is the correct tool to check and repair an unmounted XFS filesystem.

Question 2

What does 'pvmove /dev/sdb' accomplish in LVM?

Accepted Answer

Migrates all LV data off /dev/sdb to other PVs in the VG

Answer

pvmove relocates physical extents from one PV to other available PVs within the same volume group.

Question 3

In a Btrfs filesystem, what is a 'subvolume'?

Accepted Answer

An independently mountable POSIX file tree within a Btrfs volume

Answer

A Btrfs subvolume is an independently snapshotted and mountable file tree namespace within a single Btrfs volume.

Question 4

Which command shows real-time disk I/O statistics per device, including read/write throughput?

Accepted Answer

iostat -xz 1

Answer

iostat -xz 1 reports extended device statistics every second, showing throughput, utilization, and I/O wait.

Question 5

What does the 'discard' mount option enable for SSDs?

Accepted Answer

Continuous TRIM support to inform the SSD of freed blocks

Answer

The discard option sends TRIM commands to the SSD whenever blocks are freed, maintaining SSD performance over time.

(LCA) Certified Linux Administrator Practice Test