Linux Performance Monitoring & Analysis - Hands On !!

Use the dmesg command to view kernel messages and extract hardware details from the ring buffer, including cpu, memory, and network interfaces, with options like -T for readability.

Explore the dmidecode command to retrieve bios, smbios, and hardware details from sysfs on linux, including memory, cpu, types, serial number, manufacturer, and model.

Explore kernel tunables in /proc/sys to customize devices, filesystem, networking, and memory behavior. Changes write to memory immediately and are non-persistent across reboots; labs show making them permanent.

Modify kernel tunables on a running Linux system using in-memory changes, sysctl, and /etc/sysctl.d persistence, and learn to enable icmp echo and adjust tcp memory values.

Persist kernel tunables by creating a .conf file in /etc/sysctl.d, since boot loads these settings and sysctl -p can apply changes; avoid editing vendor files in /usr/lib/sysctl.d.

Practice lab demonstrates debugging a Linux SAS raid setup with the megaraid_sas module, showing how to disable msix via modprobe.d and persist changes by reloading the module.

Configure resource limits with ulimit to control memory and processes, using soft and hard limits stored in /etc/security/limits.conf and viewed with ulimit -a.

Configure persistent ulimit rules with the pam_limits module in /etc/pam.d and create a custom /etc/security/limits.d/db.conf to cap max logins for the db group at 2.

Configure memory accounting and apply a 1 gb memory limit for the county service using system CTM commands. Inspect the systemd controller files to confirm the settings.

Learn how the run queue tracks active CPU processes, how the kernel schedules them by priority, and how to monitor CPU utilization and load averages with top, sar, and uptime.

Understand how Linux memory works, including physical RAM, pages, and swap, and how the swapper moves inactive pages in and out to free memory.

Learn how to identify network issues and packet loss between linux servers using tcpdump and ifconfig, capture logs, analyze rx/tx errors, and collaborate with the network team.

Understand what a process is and how the kernel allocates memory and cpu, then view processes with ps commands and key fields like pid, ppid, cpu, and cmd.

Explore process stats, including R, D, S, T, and Z, to understand running, sleeping, stopped, zombie states, disk I/O issues, and paging with swap.

Discover how to use lsof to identify which processes open specific files, list open files under a directory, and filter by user, process name, or pid for server tuning.

Lab-1 demonstrates using the find command to locate .log files in /home, identify the owner, safely remove them, and locate empty, hidden, or user-owned files such as sverma.