LFCS Storage Management Practice Test 4 — 15 Questions

Question 1

Which two statements are true about LVM snapshots? (Choose two.)

Accepted Answer

Snapshots use copy-on-write technology.. LVM snapshots use copy-on-write (COW) technology, which means that only the data blocks that are changed after the snapshot is created are copied to the snapshot volume. This makes snapshots space-efficient, as they do not duplicate the entire original volume at creation time.

Answer

Snapshots require the same amount of space as the original volume.

Answer

Snapshots are read-only by default.

Answer

Snapshots are only supported on ext4 filesystems.

Question 2

Which three RAID levels are commonly supported in Linux software RAID? (Choose three.)

Accepted Answer

RAID 0. RAID 0 (striping) is supported in Linux software RAID via the md (multiple device) subsystem, providing improved performance by distributing data across multiple disks without redundancy. It is a standard RAID level implemented in the Linux kernel's md driver.

Answer

RAID 4

Answer

RAID 6

Question 3

Which two commands can be used to create an ext4 filesystem on a Linux block device? (Choose two.)

Accepted Answer

mke2fs -t ext4 /dev/sdb1. Both `mke2fs -t ext4` and `mkfs.ext4` are valid commands to create an ext4 filesystem. `mke2fs` is the underlying tool for creating ext2/ext3/ext4 filesystems, and the `-t ext4` flag explicitly sets the filesystem type to ext4. `mkfs.ext4` is a wrapper script that calls `mke2fs` with the appropriate options for ext4, making it a direct and commonly used alternative.

Answer

fsck.ext4 /dev/sdb1

Answer

mke2fs -j /dev/sdb1

Answer

tune2fs -O extents /dev/sdb1

Question 4

Refer to the exhibit. Which device is the root filesystem mounted from?

Accepted Answer

/dev/sda2. The root filesystem is mounted from /dev/sda2 because the output of the `mount` command shows that the device `/dev/sda2` is mounted on `/` (the root directory). This is the standard location for the root filesystem in Linux, and the mount point `/` uniquely identifies it.

Answer

/dev/sdb

Answer

/dev/sdb1

Answer

/dev/sda1

Question 5

A system administrator needs to mount the boot filesystem on a typical Linux system with MBR partitioning. Which partition should be used?

Accepted Answer

/dev/sda1. In the context of the LFCS exam, the first partition on a disk (/dev/sda1) is commonly reserved for the boot partition. This partition contains the bootloader and kernel images necessary for system startup. Option C is correct.

Answer

/dev/sda2

Answer

None of the above

Answer

/dev/sda3

Question 6

Refer to the exhibit. Which mount options are set for the root filesystem?

Accepted Answer

defaults,noatime. The root filesystem is mounted with both 'defaults' and 'noatime' options. 'defaults' includes standard options like rw, suid, dev, exec, auto, nouser, and async. 'noatime' disables updating the access time (atime) on every read, reducing disk I/O and improving performance, especially on SSDs or virtualized systems.

Answer

defaults

Answer

errors=remount-ro

Answer

noauto,user

Question 7

A database server is running out of space in its /var/lib/mysql directory. The system admin wants to add a new 100GB disk to increase storage. Which of the following steps should be performed to mount the new filesystem at /var/lib/mysql without data loss?

Accepted Answer

Partition the disk, create a filesystem, mount it at a temporary mount point, copy existing data from /var/lib/mysql to the new filesystem, unmount /var/lib/mysql (if it's a mount), mount the new filesystem at /var/lib/mysql, and update /etc/fstab.. It ensures no data loss by first copying existing data to the new filesystem mounted at a temporary point, then unmounting the old mount (if any) and remounting the new filesystem at /var/lib/mysql. This preserves the existing database files and allows the new disk to be used without disrupting the directory structure. The /etc/fstab update ensures the mount persists across reboots.

Answer

Add the new disk as an LVM physical volume, extend the volume group, extend the logical volume containing /var/lib/mysql, and then resize the filesystem.

Answer

Partition the disk, create a filesystem, add an entry in /etc/fstab, and reboot the server.

Answer

Partition the disk, create a filesystem, mount it directly to /var/lib/mysql, and then move the existing data into place.

Question 8

An administrator needs to check the UUID of a filesystem on /dev/sdb1. Which command should be used?

Accepted Answer

blkid /dev/sdb1. The `blkid` command is specifically designed to locate and display block device attributes, including the UUID and filesystem type. Running `blkid /dev/sdb1` queries the device's superblock and outputs its UUID, making it the correct tool for this task.

Answer

df -h /dev/sdb1

Answer

mount | grep sdb1

Answer

fdisk -l /dev/sdb1

Question 9

A storage administrator is troubleshooting a system where a new SCSI disk is detected by the kernel but not visible in /dev/disk/by-id/. What is the most likely cause?

Accepted Answer

The udev daemon has not processed the device yet; run 'udevadm trigger' to generate links.. When a new SCSI disk is detected by the kernel, the kernel creates the device node (e.g., /dev/sdb), but the symbolic links under /dev/disk/by-id/ are generated by udev based on the device's WWID or other identifiers. If udev has not yet processed the uevent for the new disk, those persistent by-id links will not exist. Running 'udevadm trigger' forces udev to reprocess all pending or missed uevents, which creates the missing links.

Answer

The device mapper target is not set for the disk.

Answer

The disk does not have a valid partition table.

Answer

The scsi_mod kernel module is not loaded.

Question 10

A system administrator wants to create a RAID 1 array using two whole disks /dev/sdb and /dev/sdc. They plan to use mdadm. Which command creates the array and builds it with two devices?

Accepted Answer

mdadm --create /dev/md0 --level=1 --raid-devices=2 /dev/sdb /dev/sdc. It uses the proper mdadm syntax to create a RAID 1 array: `--create` to initialize the array, `--level=1` (or `--level=raid1`) to specify mirroring, `--raid-devices=2` to indicate exactly two disks, and lists both `/dev/sdb` and `/dev/sdc`. This command builds the array with the two specified whole disks, which is the standard method for creating a RAID 1 array in Linux.

Answer

mdadm --create /dev/md0 --level=mirror --raid-disks=2 /dev/sdb /dev/sdc

Answer

mdadm --create /dev/md0 --level=raid1 --add /dev/sdb /dev/sdc

Answer

mdadm --assemble /dev/md0 /dev/sdb /dev/sdc

Question 11

After creating an XFS filesystem on /dev/sdb1, an admin mounts it and writes data. Later, they run 'xfs_info /mnt/data' and see the filesystem was created with default settings. What is the default inode size for XFS on a typical Linux system?

Accepted Answer

256 bytes. The default inode size for XFS on a typical Linux system is 256 bytes. This is set at filesystem creation time and provides a balance between supporting extended attributes (like ACLs and SELinux contexts) and minimizing metadata overhead. The `xfs_info` command confirms the default settings, which include this 256-byte inode size.

Answer

512 bytes

Answer

128 bytes

Answer

4096 bytes

Question 12

A system administrator receives a report that a server with an ext4 filesystem becomes unresponsive when a particular process writes a large file. The root filesystem is not full. Which of the following is the most likely cause?

Accepted Answer

The filesystem has experienced a corruption; running 'fsck' may resolve the issue.. Filesystem corruption can cause the system to hang when a process attempts to write to a damaged area, even if the filesystem is not full. The ext4 journal may replay inconsistent metadata, leading to an I/O stall. Running 'fsck' can detect and repair such corruption, restoring normal operation.

Answer

The journal size is too large and causes excessive disk writes.

Answer

The filesystem is mounted with the 'noatime' option, causing frequent access time updates.

Answer

The hard disk has developed bad sectors that affect only that file's location.

Question 13

Which of the following commands can be used to display the total, used, and available space for all mounted ext4 filesystems?

Accepted Answer

df -hT. The `df -hT` command displays disk space usage for all mounted filesystems, with the `-h` flag providing human-readable sizes (e.g., GB, MB) and the `-T` flag showing the filesystem type (e.g., ext4). This directly meets the requirement to show total, used, and available space for all mounted ext4 filesystems.

Answer

lsblk

Answer

fdisk -l

Answer

tune2fs -l /dev/sda1

Question 14

An administrator wants to ensure that a specific LVM logical volume is automatically resized when the underlying physical volume is extended. Which steps are required?

Accepted Answer

Extend the physical volume, extend the logical volume, and then run resize2fs (or xfs_growfs) to resize the filesystem.. After extending the underlying physical volume (PV) and the logical volume (LV), the filesystem must be resized to utilize the new space. For ext4, this is done with `resize2fs`; for XFS, `xfs_growfs` is used. LVM does not automatically resize the filesystem when the PV or LV is extended; manual intervention is required to grow the filesystem.

Answer

Add the logical volume to the volume group with '--auto-resize' flag.

Answer

Extend the physical volume, extend the logical volume, and update /etc/fstab with 'auto-resize' option.

Answer

Mount the filesystem with the 'extend' option to allow automatic resize on PV changes.

Question 15

A company's backup script fails with an error indicating 'no space left on device' on an NFS mount. The administrator checks 'df -h' on the NFS client and sees the mount is at 90% usage. However, the NFS server shows the exported filesystem is only 50% full. What is the most likely cause?

Accepted Answer

The mount point on the client (e.g., /mnt/nfs) is on a local filesystem that is full, preventing writes to the NFS mount.. The NFS mount point on the client (e.g., /mnt/nfs) is itself a directory within a local filesystem. When the local filesystem is full, the kernel cannot create or update the mount point's directory entry, causing writes to the NFS share to fail with 'no space left on device' even though the remote filesystem has free space. This is a classic client-side vs. server-side space confusion.

Answer

The 'df' command is caching old data; run 'sync' and then 'df' again.

Answer

The NFS server is overloaded and not responding in time.

Answer

The NFS export has a quota limit that is lower than the actual filesystem capacity.