I just got a new 500GB NVME drive for my RPi5. Due to the way I "installed" RPi OS on the NVME drive, I wound up with a dinky 9GB root (/) partition! So, I had to "extend" or "resize" the root partition. I've not done much of this before - being a macOS and Raspberry Pi/SD card user. Doing some research before starting, I encountered a lot of warnings and cautions, especially for doing this from the command line. But I run headless, and it really cannot be that difficult. I survived this, and thought I'd document the procedure for others - and myself when I need to do this again.
We will use four tools for this task:
lsblk --fsfdiskresize2fse2fsck
I'm sure it's possible to screw this up. I made one mis-step, but recovered easily. The command line interface is rather curt, and it uses words that invoke apprehension. For example, when resizing a partition, it must first be deleted (d). When you've got valuable data on a partition, the last thing you want to do is delete. But if you read ahead, you understand that it is not the data you are deleting, but only the partition markers.
Use this handy tool to find out about all the block devices connected to your machine. Shown below are the results for my RPi5 that has two (2) devices attached:
- an SD card with two partitions
- an NVME chip/module/card - also with two (2) partitions
You should also note that the NVME card is un-mounted - as it must be to resize its partitions. One of the nice things about the new NVME accommodations in RPI OS is the boot options. You may keep both devices connected at all times, and prioritize the boot order to favor one or the other (see raspi-config for this setup).
$ lsblk --fs
NAME FSTYPE FSVER LABEL UUID FSAVAIL FSUSE% MOUNTPOINTS
mmcblk0
├─mmcblk0p1 vfat FAT32 bootfs 146B-AD94 447.6M 12% /boot/firmware
└─mmcblk0p2 ext4 1.0 rootfs 6e6b1b32-ff98-4ac1-961e-0512bc32d36d 23.5G 14% /
nvme0n1
├─nvme0n1p1 vfat FAT32 bootfs 146B-AD94
└─nvme0n1p2 ext4 1.0 rootfs ece25014-1cd7-4874-9bfc-f91e486bc000Everything you do with the fdisk tool requires root privileges. You can probably dispense with fdisk -l as it provides scant information beyond lsblk --fs, but better to use it than not I suppose.
$ sudo fdisk -l
...
... # reams of useless data on all 16 ram disks
...
Disk /dev/nvme0n1: 465.76 GiB, 500107862016 bytes, 976773168 sectors
Disk model: CT500P3PSSD8
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: 0x8a6020b5
Device Boot Start End Sectors Size Id Type
/dev/nvme0n1p1 2048 1050623 1048576 512M c W95 FAT32 (LBA)
/dev/nvme0n1p2 1050624 19890175 18839552 9G 83 Linux
...
... # Note that it does provide Size as well as Start & End blocksNow we begin the "fun" part. Note that in the first command, the entire device is given as input, rather than the partition of interest. One could also specify the partition of interest; i.e. /dev/nvme0n1p2; it makes little difference in the end.
Note particularly that this command leads us into a command processor; the : serves as a prompt. You can enter an m for a list & brief explanation of all the commands, but you needn't do that as we'll only be using a small subset of the commands for re-sizing the NVME's root partition.
$ sudo fdisk /dev/nvme0n1 # we'll operate on the entire device rather than a single partition
Welcome to fdisk (util-linux 2.38.1).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.
Command (m for help):We will next enter 4 commands, with some details for one of them: p for print, d for delete partition, n for add new partition, and w for write partition table to disk & exit.
Following the n entry, a prompt is issued to define the beginning and ending sectors . Defaults are offered; these defaults will result in allocating all un-allocated space on the device to the new partition (new root partition).
This was where I may have mis-stepped: I began thinking :) I thought that I might want to make the boot partition a bit larger, and I might want to leave some space for "other things". And so I initially spec'd the starting sector to be 1800000, and the ending sector to be 840000000. After executing the w command, and moving to the next step (resize2fs), I got an ominous message stating "Bad magic number in super-block while trying to open /dev/nvme0n1p2" Oh shit! :)
Quickly researching this issue, I read something that suggested the cause might be the "gap" I left between the end partition p1 (boot) and the beginning of p2 (root). The solution was simple enough: re-run sudo fdisk /dev/nvme0n1, delete the new partition I'd just created, make a new(er) one, and leave no gap; i.e. start with the sector number immediately following the end of p1 (1050624) - as shown in the dialog below. Lesson learned: my thinking gets me into trouble sometimes.
Command (m for help): p
Disk /dev/nvme0n1: 465.76 GiB, 500107862016 bytes, 976773168 sectors
Disk model: CT500P3PSSD8
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: 0x8a6020b5
Device Boot Start End Sectors Size Id Type
/dev/nvme0n1p1 2048 1050623 1048576 512M c W95 FAT32 (LBA)
/dev/nvme0n1p2 1800000 840000000 838200001 399.7G 83 Linux
Command (m for help): d # <== input 'd'
Partition number (1,2, default 2): 2
Partition 2 has been deleted.
Command (m for help): n # <== input 'n'
Partition type
p primary (1 primary, 0 extended, 3 free)
e extended (container for logical partitions)
Select (default p): p # <== input 'p'
Partition number (2-4, default 2): # <== input nothing, accept default
First sector (1050624-976773167, default 1050624): # <== input nothing, accept default
Last sector, +/-sectors or +/-size{K,M,G,T,P} (1050624-976773167, default 976773167): 840000000 # <== input 840000000; leave un-allocated space for future use
Created a new partition 2 of type 'Linux' and of size 400 GiB.
Partition \#2 contains a ext4 signature.
Do you want to remove the signature? [Y]es/[N]o: n # <== input 'n'
Command (m for help): p # <== input 'p'
Disk /dev/nvme0n1: 465.76 GiB, 500107862016 bytes, 976773168 sectors
Disk model: CT500P3PSSD8
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: 0x8a6020b5
Device Boot Start End Sectors Size Id Type
/dev/nvme0n1p1 2048 1050623 1048576 512M c W95 FAT32 (LBA)
/dev/nvme0n1p2 1050624 840000000 838949377 400G 83 Linux
Command (m for help): w
The partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.I actually was not aware that e2fsck was required; I only learned after starting resize2fs.
$ sudo resize2fs /dev/nvme0n1p2
resize2fs 1.47.0 (5-Feb-2023)
Please run 'e2fsck -f /dev/nvme0n1p2' first. # <== uhhh, OK
$ sudo e2fsck -f /dev/nvme0n1p2
e2fsck 1.47.0 (5-Feb-2023)
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
rootfs: 123316/584064 files (0.1% non-contiguous), 2233090/2354944 blocks$ sudo resize2fs /dev/nvme0n1p2
resize2fs 1.47.0 (5-Feb-2023)
Resizing the filesystem on /dev/nvme0n1p2 to 104868672 (4k) blocks.
The filesystem on /dev/nvme0n1p2 is now 104868672 (4k) blocks long.
$And that's it... you should be able to reboot using your NVME card with a lot more space!