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fdisk-parted

fdisk、parted 和 gdisk 用于创建和修改磁盘分区表（MBR 和 GPT）。当用户询问关于磁盘分区、创建或删除分区、设置 GPT 或 MBR 布局、检查分区表或调整分区大小时调用。触发词包括：fdisk, parted, gdisk, 分区, 分区表, GPT, MBR, 创建分区, 调整分区大小, 磁盘设置, 新磁盘分区, 格式化磁盘, 分区方案, 4K 对齐, 分区对齐。

person作者: jakexiaohubgithub
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Identity

| Property | Value | |----------|-------| | Binaries | fdisk, parted, gdisk | | Config | No persistent config — invoked directly or interactively | | Logs | No persistent logs — changes written directly to disk | | Type | CLI tools | | Install | apt install fdisk parted gdisk / dnf install util-linux parted gdisk |

Tool Selection Guide

| Use case | Tool | |----------|------| | MBR partitioning (legacy BIOS, < 2 TB, < 4 partitions common) | fdisk | | GPT partitioning with advanced features | gdisk | | Non-interactive scripting, LVM/RAID prep | parted | | Converting MBR to GPT without data loss | gdisk (hybrid) | | Resize a partition | parted resizepart | | Align-check partitions | parted align-check |

Key Operations

| Task | Command | |------|---------| | List all partitions on all disks | sudo fdisk -l | | List partitions on a specific disk | sudo fdisk -l /dev/sdb | | Interactive MBR partition editor | sudo fdisk /dev/sdb | | Interactive GPT partition editor | sudo gdisk /dev/sdb | | parted interactive session | sudo parted /dev/sdb | | parted: print partition table | sudo parted /dev/sdb print | | parted: create GPT table | sudo parted /dev/sdb mklabel gpt | | parted: create MBR table | sudo parted /dev/sdb mklabel msdos | | parted: create a partition (non-interactive) | sudo parted /dev/sdb mkpart primary ext4 1MiB 100% | | parted: check partition alignment | sudo parted /dev/sdb align-check optimal 1 | | parted: resize a partition | sudo parted /dev/sdb resizepart 1 200GiB | | Inform kernel of table changes | sudo partprobe /dev/sdb | | Resize ext4 filesystem after partition grow | sudo resize2fs /dev/sdb1 | | Grow XFS filesystem to fill partition | sudo xfs_growfs /mountpoint |

fdisk Interactive Commands

| Key | Action | |-----|--------| | p | Print current partition table | | n | New partition | | d | Delete partition | | t | Change partition type | | g | Create new GPT table | | o | Create new MBR table | | w | Write changes and exit | | q | Quit without saving | | m | Help / list commands |

Common Failures

| Symptom | Cause | Fix | |---------|-------|-----| | fdisk creates MBR partition table by default | fdisk defaults to MBR (o) unless told otherwise | Use g in fdisk to create GPT, or use gdisk/parted for GPT-first workflow | | Partition changes not visible after fdisk exits | Kernel has the old table cached | sudo partprobe /dev/sdX; if device is busy, reboot | | "WARNING: Re-reading the partition table failed" | The disk is in use (mounted or part of active LVM/RAID) | Unmount all partitions; stop RAID/LVM; then partprobe or reboot | | Partition resized but filesystem still the same size | parted resizes the partition block device only | Grow ext4: resize2fs /dev/sdX1; XFS: xfs_growfs /mountpoint; btrfs: btrfs filesystem resize max /mountpoint | | "Error: The backup GPT table is not at the end of the disk" | GPT backup header is in wrong location (disk was resized/replaced) | sudo gdisk /dev/sdX then w and accept fix, or sudo sgdisk -e /dev/sdX | | Partitions misaligned on SSD | Start offset not on 1 MiB boundary | Use 1MiB as the start offset in parted; verify with parted /dev/sdX align-check optimal N | | Disk larger than 2 TiB not partitionable with fdisk (MBR) | MBR cannot address beyond 2 TiB | Use GPT: sudo gdisk /dev/sdX or sudo parted /dev/sdX mklabel gpt |

Pain Points

  • fdisk defaults to MBR: running fdisk /dev/sdX creates an MBR table unless you explicitly press g for GPT. For any new disk larger than 2 TB or where UEFI boot is needed, use gdisk or parted with mklabel gpt.
  • Changes only take effect after w: interactive fdisk/gdisk sessions are staged in memory. Pressing q discards all changes. Pressing w writes them immediately and irreversibly. On a live disk with data, w on a wrong table wipes the partition structure.
  • Partition resize does not resize the filesystem: parted resizepart or fdisk only changes the partition boundary in the partition table. The filesystem inside must be grown separately. For ext4 use resize2fs (online growth supported); for XFS use xfs_growfs (online); for btrfs use btrfs filesystem resize max; for shrinking ext4, unmount first, run e2fsck -f, then resize2fs, then resizepart.
  • 4K alignment matters for SSDs: starting partitions on 1 MiB boundaries ensures alignment to both 512-byte and 4096-byte physical sector boundaries. Misaligned partitions cause extra read-modify-write cycles on SSDs. Always specify start offsets in MiB when using parted non-interactively.
  • Never partition a mounted disk: partitioning a disk with active mounts risks data corruption. Unmount all partitions and deactivate LVM/RAID before editing the partition table.
  • partprobe is not always sufficient: if any partition on the disk is mounted or held by LVM/RAID, the kernel will refuse to re-read the table. A reboot is the safe fallback.

References

See references/ for:

  • cheatsheet.md — 10 task-organized patterns for common partitioning workflows
  • docs.md — man pages and upstream documentation links