Mounting an External Hard Drive in Linux
After a machine restart, the external hard drive wasn’t recognized and needed to be remounted. However, after using fdisk -l, the external hard drive was nowhere to be found, making it impossible to mount.
In practice, this kind of problem usually has two steps: first confirm whether Linux can still see the disk device, then decide whether you can mount it directly or need to rescan the bus so the device appears again.
How to Mount a Disk
First, use fdisk -l to check the current hard drive status.
➜ ~ fdisk -l
WARNING: fdisk GPT support is currently new, and therefore in an experimental phase. Use at your own discretion.
Disk /dev/sdb: 320.1 GB, 320072933376 bytes, 625142448 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: gpt
Disk identifier: AF1B577B-830C-4026-AC5F-37870D362B3C
# Start End Size Type Name
1 2048 411647 200M EFI System EFI System Partition
2 411648 2508799 1G Microsoft basic
3 2508800 625141759 296.9G Linux LVM
Disk /dev/mapper/centos-root: 53.7 GB, 53687091200 bytes, 104857600 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/mapper/centos-swap: 3623 MB, 3623878656 bytes, 7077888 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/mapper/centos-home: 261.5 GB, 261468717056 bytes, 510681088 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/sda: 1000.2 GB, 1000170586112 bytes, 1953458176 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x16f2a91f
Device Boot Start End Blocks Id System
/dev/sda1 1 4294967295 2147483647+ ee GPT
Here, my external hard drive is 1TB, so I can identify it as /dev/sda1. Then I can mount it with mount:
➜ ~ mkdir ~/60Gaug
➜ ~ mount /dev/sda1 ~/60Gaug
➜ ~ ll ~/60Gaug
total 712M
drwxrwxrwx 1 root root 0 Aug 29 09:35 169306313
-rwxrwxrwx 1 root root 481M Sep 28 12:24 backup.zip
drwxrwxrwx 1 root root 0 Sep 21 18:48 djan
-rwxrwxrwx 1 root root 375K Oct 29 08:42 download
drwxrwxrwx 1 root root 4.0K Oct 31 18:19 genome
drwxrwxrwx 1 root root 4.0K Aug 31 08:55 a
drwxrwxrwx 1 root root 8.0K Oct 8 18:33 jiali
drwxrwxrwx 1 root root 4.0K Sep 21 13:42
drwxrwxrwx 1 root root 0 Sep 21 13:31 N1800068
drwxrwxrwx 1 root root 4.0K Sep 10 15:47 1
-rwxrwxrwx 1 root root 231M Sep 28 12:31 2.zip
drwxrwxrwx 1 root root 4.0K Nov 27 14:04 3
If you only want a quick view of current disks and partitions, lsblk is often easier to read than fdisk -l:
lsblk
If the Hard Drive Is Not Recognized
1. Check the Host Bus Number
Use the command:
➜ ~ ls /sys/class/scsi_host/
host2 host3 host4 host8
2. Rescan the SCSI Bus to Add Devices
➜ ~ echo "- - -" > /sys/class/scsi_host/host2/scan
➜ ~ echo "- - -" > /sys/class/scsi_host/host3/scan
➜ ~ echo "- - -" > /sys/class/scsi_host/host4/scan
➜ ~ echo "- - -" > /sys/class/scsi_host/host8/scan
Note: Use the corresponding host numbers.
After rescanning, if the device appears when you run fdisk -l or lsblk again, you can use the mount command from the previous section.
How to Confirm the Mount Worked
After mounting, you can verify it with checks like these:
mount | grep 60Gaugto confirm the mount point is activedf -hto confirm the disk capacity appears on the target path
If you want to disconnect the drive safely later, run umount ~/60Gaug before unplugging it.
- 原文作者：春江暮客
- 原文链接：https://www.bobobk.com/en/211.html
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