Oracle Linux Kernel and System Tuning

1. What does the kernel.panic parameter specify?

Delay before automatic reboot after kernel panic

Log level for panic messages

Memory dump configuration

Process termination on critical errors

2. After modifying kernel parameters in /etc/sysctl.d/, what command ensures they load on next boot?

Sysctl -p /etc/sysctl.d/99-custom.conf

Systemctl restart sysctl

Both a and b work

Only manual /proc edits persist

3. Which system tool displays detailed I/O statistics and throughput metrics?

Iostat

Iotop

Ioctl

Ioping

4. The kernel parameter kernel.randomize_va_space enables which security feature?

Address Space Layout Randomization (ASLR)

Secure Boot validation

Memory encryption

Stack canary protection

5. What is the role of the net.core.somaxconn kernel parameter?

Maximum TCP listen queue length

Total socket buffer size

Maximum concurrent connections

TCP connection timeout value

6. Which kernel parameter adjusts the aggressiveness of the out-of-memory (OOM) killer?

Vm.oom_kill_allocating_task

Vm.oom_dump_tasks

Kernel.oom_adj

Memory.oom_control

7. The kernel.core_uses_pid parameter determines whether core dumps include what information?

Process ID in the core filename

Timestamp of the crash

Core dump compression

Signal number that caused the dump

8. What command regenerates the GRUB configuration after modifying /etc/default/grub?

Grub-mkconfig -o /boot/grub2/grub.cfg

Update-grub

Grub2-mkconfig

Both a and b

9. Which of the following is NOT a typical kernel tuning objective for Oracle Linux systems?

Reducing context switch overhead

Optimizing network buffer sizes

Changing kernel source code

Adjusting memory page caching behavior

10. The fs.inotify.max_user_watches parameter controls what resource?

Maximum watched files per user

File descriptor limit

Directory monitoring depth

Symbolic link resolution limit

11. Which file in /etc/sysctl.d/ is used to persist kernel parameter changes across reboots?

Kernel.conf

99-custom.conf

Sysctl.params

Boot.config

12. Which parameter in /etc/default/grub controls kernel command-line arguments at boot time?

GRUB_CMDLINE_LINUX

KERNEL_PARAMS

BOOT_ARGUMENTS

GRUB_KERNEL_ARGS

13. What is the primary function of the kernel.sched_migration_cost_ns parameter?

Sets CPU affinity rules

Controls task migration overhead calculation

Limits inter-processor communication

Determines load balancing frequency

14. Which command applies kernel parameter changes immediately without requiring a reboot?

Sysctl -p

Sysctl -w parameter=value

Echo value > /proc/sys/...

All of the above

15. What does the vm.dirty_ratio kernel parameter determine?

Maximum percentage of RAM for dirty pages before writeback

Threshold for page cache invalidation

Memory pressure for swap activation

Frequency of fsync operations

16. The kernel parameter net.ipv4.tcp_fin_timeout controls what aspect of TCP connections?

Maximum connection backlog

Time sockets remain in FIN_WAIT state

TCP keepalive interval

SYN flood protection threshold

17. Which tool is used to monitor real-time system performance including CPU, memory, and I/O on Oracle Linux?

Iostat

Top or htop

Vmstat

Netstat

18. What is the purpose of the vm.swappiness kernel parameter?

Controls swap partition size

Determines kernel preference for swapping versus dropping cache

Limits memory allocation to swap

Enables or disables swap functionality

19. Which kernel parameter controls the maximum number of open file descriptors per process?

Fs.file-max

Fs.open-files

Ulimit.max-files

Kernel.file-limit

20. What command displays the current value of a kernel parameter without needing to view /proc directly?

Sysctl -a

Sysctl --show