LPIC-1 Devices, Filesystems and FHS Practice Test 8 — 15 Questions

Question 1

After modifying /etc/fstab, an administrator wants to test if the new mount points can be mounted without rebooting. Which command should be used?

Accepted Answer

mount -a. The `mount -a` command reads /etc/fstab and mounts all filesystems listed there that are not already mounted, making it the correct way to test new entries without rebooting. This command respects the mount options and order defined in fstab, allowing the administrator to verify that the new mount points work correctly.

Answer

systemctl daemon-reload

Answer

mount -o remount

Answer

mount -t ext4

Question 2

A user complains that a filesystem is reporting 'Disk quota exceeded' even though the user has not stored any new files recently. What could be the cause?

Accepted Answer

The user has exceeded the inode quota. Linux filesystems enforce two types of quotas: block quotas (for disk space) and inode quotas (for the number of files and directories). If the user has not stored new files recently but still receives a 'Disk quota exceeded' error, it is likely that they have exceeded their inode quota, meaning they have created too many files or directories (each consuming an inode), even if those files are small or empty. The error message is generic and can refer to either quota type, so the inode limit is the probable cause when no recent data writes have occurred.

Answer

Symlinks are counted against the quota

Answer

Hard links are consuming additional inodes

Answer

File ownership is misconfigured

Question 3

Which TWO of the following are valid methods to specify a partition in /etc/fstab?

Accepted Answer

PARTUUID. Options A (PARTUUID), B (UUID), and C (LABEL) are all valid device specifiers in the first field of /etc/fstab. UUID= and LABEL= reference the filesystem UUID and filesystem label, while PARTUUID= references the partition-table UUID (GUID) of the partition. For example, 'UUID=1234-ABCD / ext4 defaults 0 1', 'LABEL=root / ext4 defaults 0 1', and 'PARTUUID=12345678-01 / ext4 defaults 0 1' are all valid and resolved at mount time. Options D (DEVPATH) and E (ID) are not valid fstab device specifiers; they are udev properties and are not recognized fstab tags.

Answer

DEVPATH

Answer

ID

Question 4

Which TWO of the following commands can be used to create a new filesystem on a partition?

Accepted Answer

mkfs.ext4. Option B, mkfs.ext4, is correct because it is a front-end to the mkfs family that specifically writes an ext4 filesystem onto a block device or partition, e.g. mkfs.ext4 /dev/sdb1. Option E, mkfs, is correct because it is the generic filesystem-creation utility that, when invoked with a type such as mkfs -t xfs /dev/sdb1, builds a new filesystem on the target partition. The unmarked options do not belong: fdisk (A) and parted (C) are partitioning tools that create/modify partition tables and partitions, not filesystems, and fsck (D) is a consistency-checking and repair utility for existing filesystems, not a creator.

Answer

fdisk

Answer

parted

Answer

fsck

Question 5

Refer to the exhibit. An administrator attempts to remount /mnt as read-only but receives the error shown. What is the most likely cause?

Accepted Answer

The /mnt directory is not a mount point. The error 'mount: /mnt is not a mount point' indicates that the administrator attempted to use the `remount` option on a directory that is not currently a mount point. The `mount -o remount` command only works on directories where a filesystem is already mounted; it modifies the mount options of an existing mount, not a regular directory. Since /mnt is not a mount point, the kernel rejects the operation with this specific error.

Answer

The /mnt directory is not empty

Answer

The /mnt directory does not exist

Answer

The filesystem is already mounted read-only

Question 6

A system administrator needs to locate the largest directories under /var to free up disk space. Which command is most appropriate?

Accepted Answer

du -sk /var/* | sort -rn. `du -sk /var/* | sort -rn` calculates the disk usage in kilobytes for each top-level item under /var, then sorts them numerically in reverse order, showing the largest directories first. This directly addresses the need to locate the largest directories to free up space, as `du` reports actual disk usage (including subdirectories) rather than file sizes.

Answer

df -h /var

Answer

find /var -size +100M

Answer

ls -lS /var

Question 7

A system administrator is troubleshooting a server where the /var partition is full, causing services to fail. The administrator deletes old log files in /var/log, but the available space does not increase. Which step should be taken next?

Accepted Answer

Use 'lsof /var/log' to find processes holding deleted file handles, then restart those processes.. When a file is deleted while a process still holds an open file descriptor to it, the file's data blocks are not freed until that process releases the handle. The `lsof /var/log` command identifies such processes, and restarting them forces the kernel to release the deleted inodes, thereby reclaiming the disk space. This is why option C is the correct next step.

Answer

Run 'sync; echo 3 > /proc/sys/vm/drop_caches' to clear cache.

Answer

Remount the /var partition with the 'noatime' option.

Answer

Run 'df -i' to check inode usage.

Question 8

Which TWO commands can be used to create an ext4 filesystem on a partition?

Accepted Answer

mkfs.ext4 /dev/sdb1. Option B, mkfs.ext4 /dev/sdb1, is correct because mkfs.ext4 is the dedicated front-end utility for creating an ext4 filesystem on the specified block device, invoking the ext4 filesystem code directly. Option C, mke2fs -t ext4 /dev/sdb1, is also correct because mke2fs is the underlying ext-family filesystem creation tool, and the -t ext4 flag explicitly selects the ext4 filesystem type, producing the same ext4 result. The unmarked options do not belong: mkfs.btrfs creates a Btrfs filesystem, mkfs.msdos creates a FAT filesystem, and mkfs.xfs creates an XFS filesystem, none of which are ext4.

Answer

mkfs.btrfs /dev/sdb1

Answer

mkfs.msdos /dev/sdb1

Answer

mkfs.xfs /dev/sdb1

Question 9

You are a system administrator at a hosting company. A customer reports that their website hosted on a shared LAMP server is returning error 500. The server runs Ubuntu 22.04 with Apache, MySQL, and PHP. You log in and find that the /var partition (on /dev/sda3, ext4) is almost full. You identify that the MySQL database directory /var/lib/mysql contains several large binary logs that are no longer needed. You delete the binary logs using 'rm -f /var/lib/mysql/mysql-bin.*'. However, the available space does not increase. You also notice that an inode leak is suspected. You check inode usage with 'df -i' and see that the partition has plenty of free inodes. You then check with 'lsof | grep deleted' and see several entries for mysqld holding deleted files. What is the correct procedure to free the space?

Accepted Answer

Restart the MySQL service with 'systemctl restart mysql'.. When a file is deleted while a process (like mysqld) still holds an open file descriptor to it, the file's inode remains allocated and the disk space is not freed until the process releases the descriptor. Restarting the MySQL service (systemctl restart mysql) causes mysqld to close all open file descriptors, allowing the kernel to release the deleted binary logs' inodes and reclaim the disk space.

Answer

Use 'dpkg --purge mysql-server' to completely remove MySQL, then reinstall it.

Answer

Run 'e2fsck -f /dev/sda3' to reclaim inodes and fix filesystem inconsistencies.

Answer

Move the binary logs to a different partition using 'mv /var/lib/mysql/mysql-bin.* /tmp/' and then delete them.

Question 10

Refer to the exhibit. A user tries to execute a script on a mounted filesystem but gets a permission denied error. The script has execute permissions. What is the most likely cause?

Accepted Answer

The filesystem is mounted with the 'noexec' option.. The 'noexec' mount option prevents execution of any binary or script on the filesystem, regardless of file permissions. Even if the script has execute permissions set, the kernel will refuse to execute it when the filesystem is mounted with 'noexec'. This is a common security measure on filesystems like /tmp or /home to prevent unauthorized code execution.

Answer

The script is not executable for the user.

Answer

The user does not have read permission on the script.

Answer

The filesystem is full.

Question 11

Refer to the exhibit. The 'mount -a' command fails for the NFS mount. What is the most likely cause?

Accepted Answer

The NFS server is not exporting the directory or is unreachable.. The 'mount -a' command reads /etc/fstab and attempts to mount all entries. For an NFS mount, the most common failure is that the NFS server is not exporting the specified directory or is unreachable, which causes the mount to fail with an error like 'mount.nfs: access denied by server while mounting' or 'mount.nfs: No route to host'. This is the correct answer because network-based filesystem mounts depend on server availability and export configuration.

Answer

The local mount point /mnt/nfs does not exist.

Answer

The filesystem type 'nfs' is not supported by the kernel.

Answer

The 'defaults' option is missing for the NFS entry.

Question 12

Refer to the exhibit. The system administrator notices the /var/log partition is nearly full. The syslog file is 2GB. Which command will safely reduce the size of this log file without stopping the logging daemon?

Accepted Answer

> /var/log/syslog. Using the shell redirection operator `> /var/log/syslog` truncates the file to zero length without deleting or closing its file descriptor. The syslog daemon (rsyslogd or syslogd) continues writing to the same inode, so no service interruption occurs. This is the safest method to free disk space while maintaining continuous logging.

Answer

cp /dev/null /var/log/syslog

Answer

rm /var/log/syslog && touch /var/log/syslog

Answer

mv /var/log/syslog /var/log/syslog.old

Question 13

Refer to the exhibit. An administrator wants to mount /dev/sda4 persistently by its UUID. Which line should be added to /etc/fstab?

Accepted Answer

UUID=abc-123 /mnt/data ext4 defaults 0 2. It uses the UUID= syntax to identify the filesystem by its universally unique identifier, which is the persistent method requested. The mount point is /mnt/data, the filesystem type is ext4, the mount options are defaults, and the dump and fsck order values (0 and 2) are appropriate for a non-root filesystem. This line ensures the device is mounted automatically at boot regardless of device name changes.

Answer

UUID=abc-123 /mnt/data ext4 noauto 0 2

Answer

LABEL=data /mnt/data ext4 defaults 0 2

Answer

/dev/sda4 /mnt/data ext4 defaults 0 2

Question 14

Refer to the exhibit. A user tries to write to /mnt/usb/myfile.txt as a non-root user and receives a permission denied error. What is the most likely reason?

Accepted Answer

The vfat filesystem does not support Unix permissions, and the mount options (fmask/dmask) restrict write access to root only. The vfat filesystem does not store Unix-style permissions; instead, it relies on mount options like fmask and dmask to set the effective permissions for all files and directories. If these masks are set to restrict write access to root only (e.g., fmask=0133), non-root users will receive a 'permission denied' error even if the filesystem is mounted read-write. This is a common cause of write failures on USB drives formatted with FAT/VFAT.

Answer

The filesystem is mounted read-only

Answer

The filesystem is mounted with the 'noexec' option, preventing write

Answer

The file's permissions are 644, so the user does not have write access

Question 15

An administrator needs to mount an ISO image located at /tmp/install.iso to the directory /mnt/iso. Which command will accomplish this?

Accepted Answer

mount -o loop /tmp/install.iso /mnt/iso. Mounting an ISO image requires the loop option to associate the file with a loop device, which the kernel then treats as a block device. The mount command with -o loop is the correct syntax. Other options either omit loop, use bind incorrectly, or attempt to remount a non-mounted filesystem.

Answer

mount --bind /tmp/install.iso /mnt/iso

Answer

mount -o remount,loop /tmp/install.iso /mnt/iso

Answer

mount -t iso9660 /tmp/install.iso /mnt/iso