Master Linux Storage Management: Disk Types, Partitioning (MBR/GPT) and Mounting

Storage Classification

Disks can be classified by technology (HDD vs SSD), hot‑plug capability, interface (IDE/SATA, SCSI/SAS, PCIe, FC), connection type (local, external, network) and partitioning scheme.

MBR Partitioning

MBR (Master Boot Record) supports up to 2 TB disks and a maximum of four primary partitions (or three primary plus one extended). The first 512 bytes contain the boot code (446 bytes) and the partition table (64 bytes). Example commands: fdisk -l /dev/sda Use fdisk to create primary, extended, and logical partitions, specifying start and end sectors or sizes (e.g., +100M).

GPT Partitioning

GPT (GUID Partition Table) removes the primary/extended limitation, allowing up to 128 partitions. It stores a protective MBR, a primary GPT header, and a backup at the end of the disk. Each partition entry is 128 bytes, and LBA0 is used for compatibility. gdisk /dev/sdb Typical steps: n to add a partition, choose partition number, default start sector, and size (e.g., +100M), then w to write the table.

Creating Filesystems

After partitioning, format partitions before storing data. Use mkfs to list supported filesystems; on CentOS 7 the default is XFS. Example for EXT4: mkfs.ext4 /dev/sdb1 Example for XFS:

mkfs.xfs /dev/sdb2

Mounting Partitions

Create mount points and mount partitions temporarily:

mkdir /data01
mkdir /data02
mount /dev/sdb1 /data01
mount /dev/sdb2 /data02

Verify with df -h and mount to see mount options (e.g., rw for EXT4, ro for XFS).

Persistent Mounts via /etc/fstab

Obtain UUIDs with blkid and add entries to /etc/fstab for automatic mounting at boot:

UUID=67e9447b-a6dd-47d2-a738-5598bc3c915 /data01 ext4 defaults 0 0
UUID=570e001f-162e-4ecd-8873-6d2c82c0edfb /data02 xfs ro 0 0

Run mount -a to apply the file.

Verification

Use df -Th to display filesystem types and usage, and mount to check mount options. Test write permissions by copying files to the mount points; read‑only mounts will reject write attempts.