How to partition, format, mount, and manage disk space in Linux disk management and filesystem operations?

Linux disk management and file systems are core skills for system administrators, involving disk partitioning, formatting, mounting, and maintenance operations.

Disk partitioning:

• fdisk: traditional disk partitioning tool
  • View partitions: fdisk -l
  • Enter interactive mode: fdisk /dev/sdb
  • Common commands: n (new partition), p (print partition table), d (delete partition), w (save and exit), q (exit without saving)
• parted: modern disk partitioning tool, supports GPT partition table
  • View partitions: parted -l
  • Enter interactive mode: parted /dev/sdb
  • Create partition: mkpart primary ext4 1MiB 100%
  • Set partition table: mklabel gpt
• lsblk: list block device information
• blkid: view block device UUID and filesystem type

File systems:

• Common filesystem types: ext4, xfs, btrfs, ntfs, vfat
• mkfs: create filesystem, e.g., mkfs.ext4 /dev/sdb1, mkfs.xfs /dev/sdb1
• mkfs.ext4: create ext4 filesystem
• mkfs.xfs: create xfs filesystem

Disk mounting:

• mount: mount filesystem, e.g., mount /dev/sdb1 /mnt/data
• umount: unmount filesystem, e.g., umount /mnt/data
• View mount points: mount, df -h
• /etc/fstab: automatic mount configuration file
  • Format: device mountpoint filesystem_type mount_options dump fsck
  • Example: /dev/sdb1 /mnt/data ext4 defaults 0 2
  • Use UUID: UUID=xxx /mnt/data ext4 defaults 0 2 (recommended)
  • View device UUID: blkid /dev/sdb1

Disk space management:

• df: view disk space usage, df -h (human-readable format)
• du: view directory or file size, du -sh directory (show total directory size)
• du -h --max-depth=1 /: view size of directories under root
• Clean disk space:
  • Clean package cache: apt clean (Debian/Ubuntu), yum clean all (CentOS/RHEL)
  • Clean old logs: logrotate
  • Find large files: find / -type f -size +100M

LVM (Logical Volume Management):

• pvcreate: create physical volume, e.g., pvcreate /dev/sdb1
• vgcreate: create volume group, e.g., vgcreate vgname /dev/sdb1
• lvcreate: create logical volume, e.g., lvcreate -L 10G -n lvname vgname
• lvextend: extend logical volume, e.g., lvextend -L +5G /dev/vgname/lvname
• lvreduce: shrink logical volume, e.g., lvreduce -L -5G /dev/vgname/lvname
• resize2fs: resize ext4 filesystem, e.g., resize2fs /dev/vgname/lvname
• xfs_growfs: extend xfs filesystem
• pvdisplay, vgdisplay, lvdisplay: view physical volume, volume group, logical volume information

RAID (Redundant Array of Independent Disks):

• mdadm: manage software RAID
  • Create RAID 0: mdadm --create /dev/md0 --level=0 --raid-devices=2 /dev/sdb1 /dev/sdc1
  • Create RAID 1: mdadm --create /dev/md0 --level=1 --raid-devices=2 /dev/sdb1 /dev/sdc1
  • Create RAID 5: mdadm --create /dev/md0 --level=5 --raid-devices=3 /dev/sdb1 /dev/sdc1 /dev/sdd1
  • View RAID status: cat /proc/mdstat, mdadm --detail /dev/md0

Disk performance optimization:

• Use SSD: improve I/O performance
• Adjust I/O scheduler: echo deadline > /sys/block/sda/queue/scheduler
• Increase filesystem block size: mkfs.ext4 -b 4096 /dev/sdb1
• Use noatime mount option: reduce disk writes
• Enable filesystem journaling: improve data security

Disk troubleshooting:

• View disk health: smartctl -a /dev/sda (requires smartmontools)
• View disk I/O: iostat -x 1
• View disk errors: dmesg | grep -i error
• Repair filesystem: fsck /dev/sdb1 (requires unmounting first)