Disk Management | Jungle Scripts

Checking Disk Usage

$ df -h # Filesystem disk usage
$ du -sh /var/log # Size of directory
$ du -h --max-depth=1 # Subdirectory sizes
$ lsblk # List block devices

Mounting Filesystems

$ mount /dev/sdb1 /mnt/data
$ umount /mnt/data
$ cat /etc/fstab # Persistent mounts

Partitions and Filesystems

Disks usually contain partitions (or volumes) formatted with a filesystem (ext4, xfs, btrfs, etc.). On cloud systems you’ll also see network and virtual disks.

# Identify disks + partitions
$ lsblk -f
$ sudo fdisk -l | head

# Create filesystem (example: ext4) — destructive
$ sudo mkfs.ext4 /dev/sdb1
$ sudo mkfs.xfs /dev/sdb1

⚠️ Formatting erases data. Only do this on new disks or after backups.

fstab Best Practices: use UUIDs

Device names like /dev/sdb1 can change across reboots. Use UUIDs in /etc/fstab for stable mounts.

$ blkid | head

# Example fstab line
UUID=xxxx-xxxx /mnt/data ext4 defaults,noatime 0 2

# Validate fstab safely
$ sudo findmnt --verify

When “Disk Full” isn’t space: inodes

ext-family filesystems track metadata using inodes. You can run out of inodes even with free disk space, typically due to millions of tiny files.

$ df -h
$ df -i

Finding What’s Using Space

Start broad (df) then zoom in (du). Be careful with du on huge directories—it can be slow.

$ df -hT
$ sudo du -xhd 1 /var | sort -h | tail
$ sudo du -xhd 1 /home | sort -h | tail

# Friendly interactive explorer (if installed)
$ ncdu /var

Storage Building Blocks (LVM & RAID)

In production, you’ll often see storage layers:

•LVM: flexible logical volumes that can be resized/snapshotted
•RAID: redundancy or performance across disks

$ sudo pvs
$ sudo vgs
$ sudo lvs

$ cat /proc/mdstat # RAID status

✅ Practice (15–20 minutes)

Use lsblk -f to map disks → partitions → mount points.
Run du -xhd 1 /var and identify top space consumers.
Inspect /etc/fstab and explain each column (device, mountpoint, fs type, options, dump, fsck).