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aurabindo

Member

From: Toronto

Registered: 2012-05-26

Posts: 41

Website

Root resize success, but fdisk reports old partition size

Hi,

My root was quite big at 931gb. I used a live media to resize the root to 40GB. Prior to that I had run fsck on the device and it everything went well.

After I rebooted to my distro, df -h correctly reports the new reduced size:

[root@aura-arch]: /home/aj># df -h
Filesystem      Size  Used Avail Use% Mounted on
dev             3.9G     0  3.9G   0% /dev
run             3.9G  884K  3.9G   1% /run
/dev/sda2        40G  3.9G   34G  11% /
tmpfs           3.9G   30M  3.9G   1% /dev/shm
tmpfs           3.9G     0  3.9G   0% /sys/fs/cgroup
tmpfs           3.9G  180K  3.9G   1% /tmp
/dev/sda1       510M   43M  468M   9% /boot
tmpfs           793M   12K  793M   1% /run/user/1000

But fdisk says:

[root@aura-arch]: /home/aj># fdisk -l
Disk /dev/sda: 931.5 GiB, 1000204886016 bytes, 1953525168 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: gpt
Disk identifier: 54E9E5FE-2CC2-4738-9F08-B1E764B23AC1

Device       Start        End    Sectors  Size Type
/dev/sda1     2048    1048576    1046529  511M EFI System
/dev/sda2  1050624 1953525134 1952474511  931G Linux filesystem

How can I fix this ?

ayekat

Member

Registered: 2011-01-17

Posts: 1,589

Re: Root resize success, but fdisk reports old partition size

I don't know which partition editor you use (fdisk? cfdisk? cgdisk?), but to resize the partition, you'll need to delete it, and then recreate it with the right size (note that some (grahical) partition editors might also provide an option "resize", which really just deletes and recreates the partition).

I'd suggest making the partition slightly larger than your filesystem (maybe 1 GB? just to be on the safe side). You can then grow the file system to fill up the partition.

---

pkgs │ hacks │ cfg │ blag

frostschutz

Member

Registered: 2013-11-15

Posts: 1,418

Re: Root resize success, but fdisk reports old partition size

Partitions and filesystems are different things. If you used resize2fs to shrink the filesystem, you also have to use parted resizepart to shrink the partition afterwards. Or when growing, you first have to grow the partition, then grow the filesystem. It's always 2 steps (perhaps more than 2 steps if you use additional storage layers like RAID, LUKS, LVM, ...).

You have to be very careful when shrinking partitions... if you make it smaller than the filesystem, it will break. If you used resize2fs 40G then the partition must be at least exactly 40G (GiB not GB) in size. If you used a different size then it must be different.

In parted this would be something like, for example: resizepart 2 84936703s. This way sda2 should be 40GiB in size sharp ( start 1050624s + (40[GiB]*1024[MiB]*1024[KiB]*1024[Byte]/512[Sector])s ). The size in sectors shown should be 83886080. Use 'unit s', 'print free' to verify.

Note this is just an example, you have to do your own math.

aurabindo

Member

From: Toronto

Registered: 2012-05-26

Posts: 41

Website

Re: Root resize success, but fdisk reports old partition size

Partitions and filesystems are different things. If you used resize2fs to shrink the filesystem, you also have to use parted resizepart to shrink the partition afterwards. Or when growing, you first have to grow the partition, then grow the filesystem. It's always 2 steps (perhaps more than 2 steps if you use additional storage layers like RAID, LUKS, LVM, ...).

You have to be very careful when shrinking partitions... if you make it smaller than the filesystem, it will break. If you used resize2fs 40G then the partition must be at least exactly 40G (GiB not GB) in size. If you used a different size then it must be different.

In parted this would be something like, for example: resizepart 2 84936703s. This way sda2 should be 40GiB in size sharp ( start 1050624s + (40[GiB]*1024[MiB]*1024[KiB]*1024[Byte]/512[Sector])s ). The size in sectors shown should be 83886080. Use 'unit s', 'print free' to verify.

Note this is just an example, you have to do your own math.

Ah the hypothetical bulb on top of my head just lit

I used resize2fs like you speculated, thanks a bunch!