How to to resize an ext4 partition from the command line?

Question

What's the easiest way to resize an ext4 partition (or any type partition depending on the method) from the command line (potentially with the fewest commands, but also the easiest to understand)?

Using a tool like Gparted is obviously easy in a GUI, but what about in the command line? I guess text-based GUIs can count for the answer too since it's technically still in the command line. It just needs to be easy.

By partition I mean a simple partition on a single disk of a personal computer (e.g. on a laptop). For example, I want to resize /dev/sda4. There's no RAIDs, there's not more than one disk drive, there's not anything complicated here. Just a simple partition on a single disk (/dev/sdaX on /dev/sda).

Answer 1

You can use fdisk to change your partition table while running.  Refer to Live resizing of an ext4 filesytem on Linux (on The silence of the code blog):

Disclaimer: The following instructions can easily screw your data if you make a mistake.  I was doing this on a VM which I backed up before performing the following actions.  If you lose your data because you didn’t perform a backup don’t come and complain.

...

First: Increase the disk size.

In ESXi this is simple, just increase the size of the virtual disk. Now you have a bigger hard drive but you still need to a) increase the partition size and b) resize the filesystem.

Second: Increase the partition size.

You can use fdisk to change the partition table while running.  The stock Ubuntu install has created 3 partitions: one primary (sda1), one extended (sda2) with a single logical partition (sda5) in it. The extended partition is simply used for swap, so I could easily move it without losing any data.

1. Delete the primary partition

2. Delete the extended partition

3. Create a new primary partition starting at the same sector as the original one just with a bigger size (leave some for swap)

4. Create a new extended partition with a logical partition in it to hold the swap space

   me@ubuntu:~$ sudo fdisk /dev/sda
   
   Command (m for help): p
   
   Disk /dev/sda: 268.4 GB, 268435456000 bytes
   255 heads, 63 sectors/track, 32635 cylinders, total 524288000 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 identifier: 0x000e49fa
   
      Device Boot      Start         End      Blocks   Id  System
   /dev/sda1   *        2048   192940031    96468992   83  Linux
   /dev/sda2       192942078   209713151     8385537    5  Extended
   /dev/sda5       192942080   209713151     8385536   82  Linux swap / Solaris
   
   Command (m for help): d
   Partition number (1-5): 1
   
   Command (m for help): d
   Partition number (1-5): 2
   
   Command (m for help): n
   Partition type:
      p   primary (0 primary, 0 extended, 4 free)
      e   extended
   Select (default p): p
   Partition number (1-4, default 1):
   Using default value 1
   First sector (2048-524287999, default 2048):
   Using default value 2048
   Last sector, +sectors or +size{K,M,G} (2048-524287999, default 524287999): 507516925
   
   Command (m for help): p
   
   Disk /dev/sda: 268.4 GB, 268435456000 bytes
   255 heads, 63 sectors/track, 32635 cylinders, total 524288000 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 identifier: 0x000e49fa
   
      Device Boot      Start         End      Blocks   Id  System
   /dev/sda1            2048   507516925   253757439   83  Linux
   
   Command (m for help): n
   Partition type:
      p   primary (1 primary, 0 extended, 3 free)
      e   extended
   Select (default p): e
   Partition number (1-4, default 2): 2
   First sector (507516926-524287999, default 507516926):
   Using default value 507516926
   Last sector, +sectors or +size{K,M,G} (507516926-524287999, default 524287999):
   Using default value 524287999
   
   Command (m for help): p
   
   Disk /dev/sda: 268.4 GB, 268435456000 bytes
   255 heads, 63 sectors/track, 32635 cylinders, total 524288000 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 identifier: 0x000e49fa
   
      Device Boot      Start         End      Blocks   Id  System
   /dev/sda1            2048   507516925   253757439   83  Linux
   /dev/sda2       507516926   524287999     8385537    5  Extended
   
   Command (m for help): n
   Partition type:
      p   primary (1 primary, 1 extended, 2 free)
      l   logical (numbered from 5)
   Select (default p): l
   Adding logical partition 5
   First sector (507518974-524287999, default 507518974):
   Using default value 507518974
   Last sector, +sectors or +size{K,M,G} (507518974-524287999, default 524287999):
   Using default value 524287999
   
   Command (m for help): p
   
   Disk /dev/sda: 268.4 GB, 268435456000 bytes
   255 heads, 63 sectors/track, 32635 cylinders, total 524288000 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 identifier: 0x000e49fa
   
      Device Boot      Start         End      Blocks   Id  System
   /dev/sda1            2048   507516925   253757439   83  Linux
   /dev/sda2       507516926   524287999     8385537    5  Extended
   /dev/sda5       507518974   524287999     8384513   83  Linux
   
   Command (m for help): t
   Partition number (1-5): 5
   
   Hex code (type L to list codes): 82
   Changed system type of partition 5 to 82 (Linux swap / Solaris)
   
   Command (m for help): p
   
   Disk /dev/sda: 268.4 GB, 268435456000 bytes
   255 heads, 63 sectors/track, 32635 cylinders, total 524288000 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 identifier: 0x000e49fa
   
      Device Boot      Start         End      Blocks   Id  System
   /dev/sda1            2048   507516925   253757439   83  Linux
   /dev/sda2       507516926   524287999     8385537    5  Extended
   /dev/sda5       507518974   524287999     8384513   82  Linux swap / Solaris
   
   Command (m for help): w
   The partition table has been altered!
   
   Calling ioctl() to re-read partition table.
   
   WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
   The kernel still uses the old table. The new table will be used at
   the next reboot or after you run partprobe(8) or kpartx(8)
   Syncing disks.
   
   me@ubuntu:~$ sudo reboot 
   

I noticed afterwards that I didn’t set the bootable flag but apparently you don’t really need it.

Third: Enlargen the filesystem.

You can do this with resize2fs online on a mounted partition.

me@ubuntu:~$ df -h
Filesystem      Size  Used Avail Use% Mounted on
/dev/sda1        91G   86G   12M 100% /
udev            3.9G  4.0K  3.9G   1% /dev
tmpfs           1.6G  696K  1.6G   1% /run
none            5.0M     0  5.0M   0% /run/lock
none            3.9G  144K  3.9G   1% /run/shm
none            100M   16K  100M   1% /run/user

me@ubuntu:~$ sudo resize2fs /dev/sda1
resize2fs 1.42.5 (29-Jul-2012)
Filesystem at /dev/sda1 is mounted on /; on-line resizing required
old_desc_blocks = 6, new_desc_blocks = 16
The filesystem on /dev/sda1 is now 63439359 blocks long.

me@ubuntu:~$ df -h
Filesystem      Size  Used Avail Use% Mounted on
/dev/sda1       239G   86G  142G  38% /
udev            3.9G   12K  3.9G   1% /dev
tmpfs           1.6G  696K  1.6G   1% /run
none            5.0M     0  5.0M   0% /run/lock
none            3.9G  152K  3.9G   1% /run/shm
none            100M   36K  100M   1% /run/user

Slight catch: After rebooting the swap space wasn’t active. Turned out you need to run mkswap, adjust /etc/fstab to the new UUID and turn the swap on

me@ubuntu:~$ sudo mkswap /dev/sda5 
Setting up swapspace version 1, size = 8384508 KiB
no label, UUID=141d401a-b49d-4a96-9b85-c130cb0de40a

me@ubuntu:~$ sudo swapon --all --verbose
swapon on /dev/sda5
swapon: /dev/sda5: found swap signature: version 1, page-size 4, same byte order
swapon: /dev/sda5: pagesize=4096, swapsize=8585740288, devsize=8585741312

Edit /etc/fstab to replace the UUID for the old swap partition with the new one from mkswap.

Answer 2

I'm answering this in case you have a similar situation as mine. I had to resize the FileSystem (Ext4) on a dynamic disk running Ubuntu 18.0.4 LTS as Guest. I managed to resize the disk from the Host and then resize the FileSystem.

Running the usual commands wasn't possible. For example:

$ resize2fs /dev/sda2
resize2fs 1.44.1 (24-Mar-2018)
The filesystem is already 13180160 (4k) blocks long.  Nothing to do!

and fdisk was quite complicated, also probably I had to run a LiveCD in order to work on the unmounted disk.

These two commands solved my problem easily and fast:

$ growpart /dev/sda 2
CHANGED: partition=2 start=4096 old: size=105441280 end=105445376 new: size=409595871,end=409599967

$ resize2fs /dev/sda2
resize2fs 1.44.1 (24-Mar-2018)
Filesystem at /dev/sda2 is mounted on /; on-line resizing required
old_desc_blocks = 7, new_desc_blocks = 25
The filesystem on /dev/sda2 is now 51199483 (4k) blocks long.

Note: 2 in the first command indicates the partition number on the device /dev/sda.

Answer 3

If you're going to be increasing the size of both the partition and the filesystem, then first run fdisk to increase the size of the partition, and then run resize2fs to increase the size of the filesystem.

If you're going to be shrinking the size of both, run resize2fs first and then run fdisk.

Answer 4

A scriptable method, assuming that there is free space directly after the partition to be resized:

echo "- +" | sfdisk -N <partnum> /dev/sdX

...followed by resize2fs /dev/sdX<partnum>.

The - tells sfdisk to reuse the existing start sector, and the + tells it to make the size as large as possible given the available space.

Answer 5

gparted uses resize2fs to change the partition's size. It doesn't take many arguments. Below are the ones I've found useful.

-M shrinks to the file system's minimum size.

-p shows a percentage indicator.

-P prints the file system's minimum size and exits.

Answer 6

The solution of noalo is obviously the best of all; so much simpler than the others:

echo "- +" | sfdisk -N <partnum> /dev/sdX

Short explanation on how it works: -N means sfdisk will work on a single partition. When started like that, sfdisk will be interactive and wait for a start position, a size, and optionally a partition type. "-" means the start position is not changed, "+" means the end position will use as much space as possible. After that you would have to use the print and write commands. The leading echo "- +" | does that in one line.

Its limitation is that there must be free space directly after. If, after the partition to resize, there is a swap partition (which means no real data inside), it can be solved as easily by sfdisk. Using the above syntax, suppose the partition to change is on sda1 and swap on sda2, we have a 128 G disk, and we want 6 G of swap: The first step is to move the swap partition to the end:

echo "122G +" | sfdisk -N2 /dev/sda

Now expand the first partition:

echo "- +"    | sfdisk -N1 /dev/sda

and resize it with resize2fs. You may have to ensure your new swap is recognized.  See swapoff, mkswap, swapon and the fstab file.  This is not within the scope of this question.

About the command for sda2: DO NOT move a partition with data this way!!!  You would lose all your data.  This command does not move the data; just the partition boundaries.  There is no danger with the command used for sda1 (- +) because the start position of the partition is not changed; this is the meaning of "-", when used for a single partition.

Thank you @noalo

Answer 7

Resize a Linux Root Partition Without Rebooting

Introduction

A typical Linux server deployed from a ProfitBricks supplied image has a single storage volume, /dev/vda. If we take a look at that using fdisk we will see that the disk is divided into two partitions. The first one, /dev/vda1, is the boot partition where the OS resides. The second partition, /dev/vda2, is configured as swap space.

root@debian:~# fdisk -l /dev/vda
Disk /dev/vda: 50 GiB, 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
Disklabel type: dos
Disk identifier: 0x0041f8a8
Device     Boot    Start       End  Sectors Size Id Type
/dev/vda1           2048  96471039 96468992  46G 83 Linux
/dev/vda2       96471040 104857599  8386560   4G 82 Linux swap / Solaris

In the example above, the total 50 GB storage volume is split into 46 GB usable space and 4 GB for swap. What if after provisioning we find that 46 GB of disk space is not enough but we prefer not to add an additional storage volume? The goal is to increase the amount of disk space available on the root filesystem. This can be accomplished with minimal disruption. We do not need to reboot the server!

Requirements

• A Linux Server created from a ProfitBricks supplied image.
• SSH or console access (via the DCD) to the Linux Server.
• The partprobe command. Can be installed from the parted package on most Linux distributions.
• The fdisk, swapoff, mkswap, swapon, and resize2fs commands. Likely available by default.
• A current snapshot or other backup of the system you are working on. Just to be safe!

Provision Additional Space

To increase the size of the hard drive, go into the DCD (Data Center Designer) and upscale the drive.

After you have increased the amount of drive space, click on "provisioning" to process the change. Takes around a minute and your hard drive is bigger.

We then need to switch off the swap - so make sure you can live a few minutes without swap space:

root@debian:~# swapoff -a

Once swap has been disabled, we need to reconfigure the partitions using fdisk:

We will delete the two existing partitions first. We run fdisk /dev/vda and then use the d command to delete partition 2, and then delete partition 1. Follow the example below:

root@debian:~# fdisk /dev/vda
Command (m for help): d
Partition number (1,2, default 2):
Partition 2 has been deleted.
Command (m for help): d
Selected partition 1
Partition 1 has been deleted.

Now we recreate our partitions. In the example we have 4 GB of swap space. So we need to keep at least that much space available for the new swap partition.

Recreate /dev/vda1 first. Press n to create a new partition. Enter p to create a primary partition. We can press Enter to accept the default value of 2048 for the first sector. Then enter a size for the partition. You can enter a value in GB, so if we are increasing the disk to 100 GB, we subtract our 4 GB for swap, and enter +96G for 96 GB.

Command (m for help): n
Partition type
   p   primary (0 primary, 0 extended, 4 free)
   e   extended (container for logical partitions)
Select (default p): p
Partition number (1-4, default 1): 1
First sector (2048-209715199, default 2048):
Last sector, +sectors or +size{K,M,G,T,P} (2048-209715199, default 209715199): +96G
Created a new partition 1 of type 'Linux' and of size 96 GiB.

Now we recreate the swap partition following a simalar process. Press n and then p to create a new primary partition. Press Enter to accept the default value for "First sector". We can also press Enter again to accept the default value for "Last sector".

Command (m for help): n
Partition type
   p   primary (1 primary, 0 extended, 3 free)
   e   extended (container for logical partitions)
Select (default p): p
Partition number (2-4, default 2): 2
First sector (201328640-209715199, default 201328640):
Last sector, +sectors or +size{K,M,G,T,P} (201328640-209715199, default 209715199):
Created a new partition 2 of type 'Linux' and of size 4 GiB.

Since this second partition is going to be used for swap space, we need to change the partition type. This can be done by pressing t at the fdisk prompt. We then press 2 to select the second partition. If you want to see the list of available partition types, press L, otherwise enter 82 to select "Linux swap / Solaris".

Command (m for help): t
Partition number (1,2, default 2): 2
Partition type (type L to list all types): L
0  Empty           24  NEC DOS         81  Minix / old Lin bf  Solaris
1  FAT12           27  Hidden NTFS Win 82  Linux swap / So c1  DRDOS/sec (FAT-
2  XENIX root      39  Plan 9          83  Linux           c4  DRDOS/sec (FAT-
3  XENIX usr       3c  PartitionMagic  84  OS/2 hidden or  c6  DRDOS/sec (FAT-
4  FAT16 <32M      40  Venix 80286     85  Linux extended  c7  Syrinx
5  Extended        41  PPC PReP Boot   86  NTFS volume set da  Non-FS data
6  FAT16           42  SFS             87  NTFS volume set db  CP/M / CTOS / .
7  HPFS/NTFS/exFAT 4d  QNX4.x          88  Linux plaintext de  Dell Utility
8  AIX             4e  QNX4.x 2nd part 8e  Linux LVM       df  BootIt
9  AIX bootable    4f  QNX4.x 3rd part 93  Amoeba          e1  DOS access
a  OS/2 Boot Manag 50  OnTrack DM      94  Amoeba BBT      e3  DOS R/O
b  W95 FAT32       51  OnTrack DM6 Aux 9f  BSD/OS          e4  SpeedStor
c  W95 FAT32 (LBA) 52  CP/M            a0  IBM Thinkpad hi ea  Rufus alignment
e  W95 FAT16 (LBA) 53  OnTrack DM6 Aux a5  FreeBSD         eb  BeOS fs
f  W95 Ext'd (LBA) 54  OnTrackDM6      a6  OpenBSD         ee  GPT
10  OPUS            55  EZ-Drive        a7  NeXTSTEP        ef  EFI (FAT-12/16/
11  Hidden FAT12    56  Golden Bow      a8  Darwin UFS      f0  Linux/PA-RISC b
12  Compaq diagnost 5c  Priam Edisk     a9  NetBSD          f1  SpeedStor
14  Hidden FAT16 <3 61  SpeedStor       ab  Darwin boot     f4  SpeedStor
16  Hidden FAT16    63  GNU HURD or Sys af  HFS / HFS+      f2  DOS secondary
17  Hidden HPFS/NTF 64  Novell Netware  b7  BSDI fs         fb  VMware VMFS
18  AST SmartSleep  65  Novell Netware  b8  BSDI swap       fc  VMware VMKCORE
1b  Hidden W95 FAT3 70  DiskSecure Mult bb  Boot Wizard hid fd  Linux raid auto
1c  Hidden W95 FAT3 75  PC/IX           bc  Acronis FAT32 L fe  LANstep
1e  Hidden W95 FAT1 80  Old Minix       be  Solaris boot    ff  BBT
Partition type (type L to list all types): 82

fdisk helpfully informs us that we have changed the partition type with the message:

Changed type of partition 'Linux' to 'Linux swap / Solaris'.

After that, we save using the w command and are returned to a shell prompt:

Command (m for help): w

You may get a message like this before the shell prompt:

The partition table has been altered.
Calling ioctl() to re-read partition table.
Re-reading the partition table failed.: Device or resource busy
The kernel still uses the old table. The new table will be used at the next reboot or after you run partprobe(8) or kpartx(8).

Lets forgo rebooting and instead tell the kernel about the new partitions using partprobe:

root@debian:~# partprobe

We should be returned to the shell prompt with no output from partprobe.

Now we need to resize our filesystem on /dev/vda1:

root@debian:~# resize2fs /dev/vda1
resize2fs 1.42.12 (29-Aug-2014)
Filesystem at /dev/vda1 is mounted on /; on-line resizing required
old_desc_blocks = 2, new_desc_blocks = 3

The filesystem on /dev/vda1 is now 25165824 (4k) blocks long.

Initialize the new swap location of /dev/vda2:

root@debian:~# mkswap /dev/vda2
Setting up swapspace version 1, size = 4193276 KiB
no label, UUID=c55c25a2-a386-4653-8455-4d9030586dd2

Finally we edit /etc/fstab and replace the old UUID with the new one returned in the output of the mkswap command. The line to change has no value for "mount point" and has "type" set to swap.

# /etc/fstab: static file system information.
#
# Use 'blkid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point>   <type>  <options>       <dump>  <pass>
UUID=332f8fb5-ff1f-4297-b512-f2c93a277296 /               ext4    errors=remount-ro 0       1
/dev/fd0        /media/floppy0  auto    rw,user,noauto,exec,utf8 0       0
UUID=c55c25a2-a386-4653-8455-4d9030586dd2       none    swap    sw      0       0

After editing /etc/fstab, we need to enable swap again:

root@debian:~# swapon -a

Verify

We can verify the new larger disk size by utilizing df and/or fdisk.

Device     Boot     Start       End   Sectors Size Id Type
/dev/vda1            2048 201328639 201326592  96G 83 Linux
/dev/vda2       201328640 209715199   8386560   4G 82 Linux swap / Solaris

We can also confirm that the server was not rebooted by looking at the output of uptime:

$ uptime
 23:54:21 up 7 days,  1:15,  1 user,  load average: 0.00, 0.01, 0.05

Summary

We have successfully increased the amount of disk space available on our Linux server.

Reference

https://devops.ionos.com/tutorials/increase-the-size-of-a-linux-root-partition-without-rebooting/

OR

https://web.archive.org/web/20201113021238/https://devops.ionos.com/tutorials/increase-the-size-of-a-linux-root-partition-without-rebooting/

Answer 8

The easy way:

I had an issue with gparted not wanting to resize

#sudo parted had no such issue

Model: ATA CT1000MX500SSD1 (scsi)
Disk /dev/sda: 1000GB
Sector size (logical/physical): 512B/4096B
Partition Table: gpt
Disk Flags: 

Number  Start   End     Size    File system  Name                  Flags
 1      1049kB  538MB   537MB   fat32        EFI System Partition  boot, esp
 2      538MB   1000GB  1000GB  ext4

(parted) resizepart 2 800GB
Warning: Partition /dev/sda2 is being used. Are you sure you want to continue?
Yes/No? yes                                                               
Warning: Shrinking a partition can cause data loss, are you sure you want to
continue?
Yes/No? yes