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Justin
Asked: 2012-11-24 23:56:48 +0800 CST

How to view if partitions primary or secondary in Linux

  • 772

How do I view my partitions if they are primary or secondary in Linux CentOS? I tried df -T but it does not show if partitions are primary or secondary.

linux

6 Answers

  1. Use this command: sudo parted /dev/sda followed by print. It outputs:

    GNU Parted 3.2
Using /dev/sda
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) print                                                            
Model: ATA WDC WD10JPVX-60J (scsi)
Disk /dev/sda: 1000GB
Sector size (logical/physical): 512B/4096B
Partition Table: msdos
Disk Flags: 

Number  Start   End    Size    Type      File system  Flags
 1      1049kB  525MB  524MB   primary   ntfs
 2      525MB   132GB  131GB   primary   ntfs         boot
 3      132GB   461GB  329GB   primary   ntfs
 4      461GB   966GB  505GB   extended               lba
 6      461GB   566GB  105GB   logical   ext4
 5      566GB   896GB  330GB   logical   ntfs
 7      896GB   966GB  70.0GB  logical   ext4

    You can check if the partition is primary or extended from this. Hope this helps!

    • 7
  2. Best Answer

    Use the cfdisk command. 

    cfdisk /dev/sda
    • 4

  3. Try fdisk -l and df -T and align the devices fdisk reports to the devices df reports. A standard MBR disk can contain only 4 primary partitions or 3 primary and 1 extended. If you have partitions numbered >= 5 they are logical partitions (with the extended partition hosting them being always number 4 i.e. /dev/sda4).

    • 1

  4. Use "fdisk -l", but look at the "Start"/"End" sectors instead of sdan numbers. If there is any overlap between Devices, there are extended/logical partitions.

    Here is an abstraction for MBR scheme. Be aware the sda2 starts from 1001470 and ends at 1000214527, covering the following 4 partitions range. It's identified as Extended partition and sda5 ~ sda8 are logical partitions.

    $ sudo fdisk -l
Disk /dev/sda: 477 GiB, 512110190592 bytes, 1000215216 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: dos
Disk identifier: 0x000e5c64

Device     Boot     Start        End   Sectors   Size Id Type
/dev/sda1  *         2048     999423    997376   487M 83 Linux
/dev/sda2         1001470 1000214527 999213058 476.5G  5 Extended
/dev/sda5         1001472   40060927  39059456  18.6G 83 Linux
/dev/sda6        40062976   79122431  39059456  18.6G 83 Linux
/dev/sda7        79124480  977559551 898435072 428.4G 83 Linux
/dev/sda8       977561600 1000214527  22652928  10.8G 82 Linux swap / Solaris
...

    Here is an example of GPT partition scheme. There are all Primary partitions. No Extended partition. 

    $ sudo fdisk -l    
Disk /dev/sda: 477 GiB, 512110190592 bytes, 1000215216 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
Disklabel type: gpt
Disk identifier: 079BF6C7-D69B-4188-B3AD-8BFE39D0F289

Device         Start        End   Sectors   Size Type
/dev/sda1       2048     616447    614400   300M Windows recovery environment
/dev/sda2     616448    1638399   1021952   499M EFI System
/dev/sda3    1638400    1900543    262144   128M Microsoft reserved
/dev/sda4    1900544  206700543 204800000  97.7G Microsoft basic data
/dev/sda5  206700544  956700671 750000128 357.6G Linux filesystem
/dev/sda6  956700672  957700095    999424   488M Linux filesystem
/dev/sda7  957700096 1000214527  42514432  20.3G Linux swap
...

    These are from Ubuntu machines.

    • 1

  5. What are the names of the partitions? primary partitions are numbered 1 to 4, for example: sda1, hdb2, etc...

    Whereas logical partitions are numbered 5 and above.

    The primary extended partition is always numbered 4.

    Check link for info

    • 0

  6. cat /proc/partitions

    You'll get something like this:

    major minor  #blocks  name

   8     0  488386584 sda
   8     1   52436128 sda1
   8     2          1 sda2
   8     5    2104483 sda5
   8     6   20972826 sda6
   8     7   52436128 sda7
   8     8  360434308 sda8
 179     0    3979776 mmcblk0
 179     1    3975680 mmcblk0p1
    • If the partition number (minor) is between 1 and 4, it is either primary or extended. The extended one will have 1 in the #blocks column (above, it's sda2).
    • If the partition number is 5 or higher, it is logical.
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