Arch Unused Disk Space

Question

I am new to the arch environment, and while the installation I remember that I allocated manually for sda1 and sda2 during partitioning, and sda3 would have taken the un-allocated memory available and so I didn't mention it. But I guess I messed up since the remaining memory was almost 700gigs, but just after using 70gigs from /home, my machine reports that it's running out of space and only 800MB is remaining in the disk space for /home. Is there anything I could do now to occupy the memory or should I re-install the arch?

For sudo fdisk -l /dev/sda

Disk /dev/sda: 931.51 GiB, 1000204886016 bytes, 1953525168 sectors
Disk model: WDC WD10JPVX-60J
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: 6A95D9F2-7B1C-394D-85AC-800EC8F01866

Device      Start        End        Sectors        SizeType
/dev/sda1   2048       1026047      1024000     500M EFI System
/dev/sda2   1026048    63940607     62914560    30G Linux filesystem
/dev/sda3   63940608   1953525134   1889584527  901G Linux filesystem

For lsblk -o +FSTYPE,FSSIZE,FSUSED /dev/sda

NAME   MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT FSTYPE FSSIZE FSUSED
sda      8:0    0 931.5G  0 disk  
├─sda1   8:1    0   500M  0 part            vfat  
├─sda2   8:2    0    30G  0 part /          ext4    29.4G  27.2G
└─sda3   8:3    0   901G  0 part /home      ext4   885.9G  56.2G

Answer 1

Your root/system partition is running out of space.

For a quick fix try to clear the pacman cache

sudo paccache -r -k 1

Also see what systemd journal is using:

journalctl --disk-usage

You can limit its size with

sudo mkdir -p /etc/systemd/journald.conf.d/
sudo sh -c 'echo -e "[Journal]\nSystemMaxUse=50M" > /etc/systemd/journald.conf.d/00-journal-size.conf'
sudo systemctl restart systemd-journald

There is also an utility called ncdu that can help you find out what it using your space.

sudo pacman -S ncdu
sudo ncdu -ex /