Scenario practice questions

Refer to the exhibit. After adding a new disk to the system, the device /dev/sdb appears. However, the administrator cannot create partitions on /dev/sdb using fdisk. What is the most likely reason?

Network Topology

Trap 1: The disk is mounted and cannot be partitioned.

Even if mounted, fdisk can still modify the partition table (though it may warn).

Trap 2: The disk does not have a valid partition table.

fdisk can create a new partition table on a disk without one.

Trap 3: The kernel does not support the disk's interface.

The device exists, so the kernel supports it.

A
The disk is currently in use as a physical volume for LVM.
Active LVM physical volumes cannot be partitioned with fdisk; the PV must be removed first.
B
The disk is mounted and cannot be partitioned.
Why wrong: Even if mounted, fdisk can still modify the partition table (though it may warn).
C
The disk does not have a valid partition table.
Why wrong: fdisk can create a new partition table on a disk without one.
D
The kernel does not support the disk's interface.
Why wrong: The device exists, so the kernel supports it.

Question 2mediummultiple choice

You are the system administrator for a small business running a Red Hat Enterprise Linux 8 server that hosts a MySQL database and a web server. The server has two physical disks: a 240GB SSD (sda) with partitions sda1 (boot), sda2 (root), sda3 (swap), and a 1TB HDD (sdb) with a single partition sdb1 mounted at /var/lib/mysql. The server has been running for months without issues. However, this morning you receive alerts that the MySQL database is not accepting new connections. You log in and find that the /var filesystem is 100% full. You check the disk usage and see that /var/lib/mysql uses 90% of the space, but there are also large log files in /var/log/httpd. To free up space immediately and restore database service while planning a permanent solution, you decide to compress old log files and move some database archives to a backup server. After compressing several log files with gzip, the available space increases by only a few MB. You then delete some old database backups from /var/lib/mysql/backup, but the space usage shown by df remains unchanged. What is the most likely cause of this behavior?

Trap 1: The disk quota for the mysql user is exceeded, so deletions do not…

Disk quotas limit usage but do not cause deletions to not free space; after deletion, quota usage decreases.

Trap 2: The SSD is not TRIM-enabled, so deleted blocks are not reclaimed.

TRIM is an optimization for SSDs; lack of TRIM does not prevent space from being freed when files are deleted; the space becomes available immediately.

Trap 3: The filesystem was remounted read-only due to errors, so deletions…

If the filesystem were remounted read-only, df would still reflect the usage before remount, and deletions would fail. But the administrator said deletions succeeded (df unchanged).

A
Some processes have open file handles to the deleted files, preventing the space from being released.
When a file is deleted but still open, the space is not freed until the file handle is closed. Use lsof to identify the processes.
B
The disk quota for the mysql user is exceeded, so deletions do not reduce usage.
Why wrong: Disk quotas limit usage but do not cause deletions to not free space; after deletion, quota usage decreases.
C
The SSD is not TRIM-enabled, so deleted blocks are not reclaimed.
Why wrong: TRIM is an optimization for SSDs; lack of TRIM does not prevent space from being freed when files are deleted; the space becomes available immediately.
D
The filesystem was remounted read-only due to errors, so deletions are not permanent.
Why wrong: If the filesystem were remounted read-only, df would still reflect the usage before remount, and deletions would fail. But the administrator said deletions succeeded (df unchanged).

Question 3easymultiple choice

Which FHS directory contains essential binaries needed for booting and repairing the system, even before /usr is mounted?

Trap 1: /boot

Contains boot loader files, not command binaries.

Trap 2: /usr/bin

/usr/bin may not be available if /usr is not mounted.

Trap 3: /sbin

Contains system binaries, but both /bin and /sbin are essential; however, /bin is more basic.

A
/boot
Why wrong: Contains boot loader files, not command binaries.
B
/usr/bin
Why wrong: /usr/bin may not be available if /usr is not mounted.
C
/sbin
Why wrong: Contains system binaries, but both /bin and /sbin are essential; however, /bin is more basic.
D
/bin
Contains essential binaries like ls, mount, etc.

Question 4mediummultiple choice

A server has a partition /dev/sda2 that is almost full. The admin suspects a large file has been deleted but is still held open by a process. Which command can identify such a file?

Trap 1: du -sh /

Shows disk usage but does not list open files.

Trap 2: find / -size +100M

Finds large files but cannot detect deleted open files.

Trap 3: df -h

Shows filesystem usage but not individual files.

A
du -sh /
Why wrong: Shows disk usage but does not list open files.
B
find / -size +100M
Why wrong: Finds large files but cannot detect deleted open files.
C
lsof | grep deleted
Shows open files marked as deleted.
D
df -h
Why wrong: Shows filesystem usage but not individual files.

Question 5hardmultiple choice

An ext4 filesystem is experiencing performance degradation due to very frequent small writes. Which tune2fs option can help by reserving a percentage of blocks for the root user to prevent fragmentation?

Trap 1: -i 0

-i sets check interval in days.

Trap 2: -g root

-g sets the group that can use reserved blocks, not the percentage.

Trap 3: -c 0

-c sets max mount count before forced fsck, not reserved blocks.

A
-i 0
Why wrong: -i sets check interval in days.
B
-g root
Why wrong: -g sets the group that can use reserved blocks, not the percentage.
C
-c 0
Why wrong: -c sets max mount count before forced fsck, not reserved blocks.
D
-m 0
-m sets reserved block percentage; setting to 0 frees space for all users but may increase fragmentation.

Question 6hardmultiple choice

You are a Linux administrator for a company that uses a custom RPM-based distribution. The development team has built a new version of the internal tool 'monitor-app' (version 2.0) and placed the RPM package in a local YUM repository located at http://internal.repo/monitor-app-2.0.el7.x86_64.rpm. The repository metadata has been updated using 'createrepo'. On a test server running CentOS 7, you run 'yum update monitor-app' but the system reports 'No packages marked for update'. The currently installed version is 1.0. You verify that the repository is enabled and accessible via 'yum repolist'. What is the most likely cause and the correct course of action?

Trap 1: Download the RPM and install it locally with 'rpm -Uvh…

This bypasses the repository and dependency resolution.

Trap 2: Check the version number in the repository using 'yum info…

If the package is not found, info will also fail.

Trap 3: Run 'yum clean all' and then 'yum update monitor-app' again

Cleaning cache may help if metadata is stale, but the package is not found.

A
Download the RPM and install it locally with 'rpm -Uvh monitor-app-2.0.el7.x86_64.rpm'
Why wrong: This bypasses the repository and dependency resolution.
B
Run 'yum list available | grep monitor' to see if the package is listed with a different name, then install it with the exact name
This identifies the exact package name in the repository.
C
Check the version number in the repository using 'yum info monitor-app' and compare with installed version
Why wrong: If the package is not found, info will also fail.
D
Run 'yum clean all' and then 'yum update monitor-app' again
Why wrong: Cleaning cache may help if metadata is stale, but the package is not found.