Linux File System Management

Linux File Systems
File systems EXT released in April of 1992 with 2GB Maximum & Filename 255 Character Max

EXT2 File System

Block Size	1KB	2KB	4KB	8KB
Max File Size	16GB	256GB	2TB	64TB
Max FS Size	2TB	8TB	16TB	32TB

Linux File System Structure & Quick "Good to Know" notes
/ - ROOT DIRECTORY
/boot - Boot Directory
/boot/linus#.#.# - Kernel
/boot/(boot loader) - Boot Loader Directory
/bin - Binary Executibles
/dev - Devices directory
/etc - Configuration Files
/etc/inittab - Default Runlevel Configuration File
/home or ~ - Home Directory for user files /Home/user = ~/
/lib - Binaries to Support Executibles
/lib64 - Binaries to support 64-bit Executibles
/lost+found -
/media - Directory to mount File Systems, CD's and removeable devices
/mnt - Mounted Filesystems or Network Shares
/opt - Optional Software
/proc - Medium of communication with I/O devices, the Kernel, and users. Example; Drivers
/root - Root Home Directory
/sbin - Administrative Binaries for Root user
/srv - Data for services
/tmp - Temporary files... e.g.; Compiling programs..etc
/usr - System files
/var - System logs, spools, & lock files.
SWAP - Virtual RAM/Paging File to switch memory binary data from Memory to Hard disk.

Linux Runlevels

Runlevel	Name	Login Environment	Networking	File System
1	Halt	NA	NA	NA
2	Single User	CLI	Down	Mounted
3	Multi-User w/o NFS	CLI	Up(Partial)	Mounted
4	Multiuser	CLI	NA	NA
5	User Defined/Unused	X GUI	Up	Mounted
6	Reboot	NA	NA	NA

An important note if it wasn't already obvious, never configure /etc/inittab to run level 0 or 6. You will end up wondering why your Linux box never boots up or always shuts down immediately after boot.

To change your Runlevel without configuring Inittab is fairly simple. This example below is to change to Runlevel 3. Now with Runlevels we have to wonder what services we're enabling or disabling. We'll save daemon/services for another page.

[root@servername]# /sbin/telinit 5