File Systems and Storage

File Systems and Storage

File systems organise how data is stored and retrieved. Understanding Linux file systems, hierarchy, and storage management is fundamental.

File Hierarchy (FHS)

/ (root), /home (users), /etc (config), /var (logs), /tmp (temporary), /usr (programs), /bin//sbin (binaries), /dev (devices), /proc//sys (kernel info).

File System Types

ext4 (default, journaling), XFS (high-performance, RHEL default), Btrfs (copy-on-write, snapshots), ZFS (data integrity), swap (virtual memory), tmpfs (RAM-based).

Disk Management

lsblk (list devices), fdisk/gdisk (partition), mkfs (create FS), mount/umount, /etc/fstab (auto-mount), df (space), du (directory sizes).

LVM

Physical Volumes (PV), Volume Groups (VG), Logical Volumes (LV). Enables resizing, snapshots, spanning disks without downtime.

RAID

RAID 0 (striping, speed), RAID 1 (mirroring, redundancy), RAID 5 (parity), RAID 10 (mirrored stripes). Software RAID via mdadm.

Backups

Full, incremental, differential. Tools: rsync, tar, dd. 3-2-1 rule: 3 copies, 2 media, 1 off-site.

Summary

Linux file systems and storage — hierarchy, LVM, RAID, backups — are core sysadmin skills ensuring data integrity and recoverability.