Linux File System Management

Linux File Systems
File systems EXT released in April of 1992 with 2GB Maximum & Filename 255 Character Max, EXT3 was EXT2 released but now with Journaling. Ext4 is the same as Ext3 but released to support 64-bit file system sizes.

 

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. Not a real Directory.
/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.

Another method of identifying non-real paths is the command below. Look at all of the mounted file systems that use 0/0/0 and have "-" under usage. These are all fictitious partitions that do not exist except when the kernel is running. These are just partitions active in memory and have no impact at all on disk space for the operating system.

[root@server ~]# df -a
Filesystem     1K-blocks    Used     Available Use% Mounted on
/dev/sda3      9920624      802144   8606412     9% /
proc           0            0        0            - /proc
sysfs          0            0        0            - /sys
devpts         0            0        0            - /dev/pts
/dev/sdb3     988116        17768    919344      2% /tmp
/dev/sda5     4956284       556536   4143916    12% /home
/dev/sda2     9920624       5292352  4116204    57% /var
/dev/sdb1     15872604      2265780  12787512   16% /usr
/dev/sda1     194442        33772    150631     19% /boot
tmpfs         964224        0        964224      0% /dev/shm
none          0             0        0            - /proc/sys/fs/binfmt_misc
sunrpc        0             0        0            - /var/lib/nfs/rpc_pipefs
nfsd          0             0        0            - /proc/fs/nfsd
/dev/hdc      3616690       3616690  0         100% /media/RHEL_5.5 x86_64 DVD
/dev/sdc1     988212        17648    920364      2% /sambashares/share1