How to make sda1 bigger / use default download files in sdb1

Question

I run below command in ubuntu:

df -h

Output:

Filesystem      Size  Used Avail Use% Mounted on
udev            111G     0  111G   0% /dev
tmpfs            23G  8.7M   23G   1% /run
/dev/sda1        29G   22G  6.8G  77% /
tmpfs           111G     0  111G   0% /dev/shm
tmpfs           5.0M     0  5.0M   0% /run/lock
tmpfs           111G     0  111G   0% /sys/fs/cgroup
none             64K     0   64K   0% /etc/network/interfaces.dynamic.d
/dev/sdb1       3.0T   72M  2.9T   1% /mnt
tmpfs            23G     0   23G   0% /run/user/1000

As stated /dev/sda1 is getting full because of high amount of data download. And /dev/sdb1 is unused. How can I make it sda1 bigger or default download packages in sdb1?

sudo blkid

/dev/sr0: UUID="0E25076072645f72" LABEL="rd_rdfe_stable.160802-0931" TYPE="udf"
/dev/sda1: LABEL="cloudimg-rootfs" UUID="b2e47a31-37fe-4914-b333-bd1c2a2dacae" TYPE="ext4" PARTUUID="c74ad4d8-01"
/dev/sdb1: UUID="5ca1e85e-5631-473a-869f-27b6dafb2d20" TYPE="ext4" PARTUUID="75cef133-3c23-4d58-a1b6-dab98f8b633c"

Upon running this command:

sudo vi /etc/fstab

CLOUD_IMG: This file was created/modified by the Cloud Image build process UUID=b2e47a31-37fe-4914-b333-bd1c2a2dacae / ext4 defaults,discard 0 0

CLOUD_IMG: This file was created/modified by the Cloud Image build process

The following is used to dynamically configured additional

NICs. Do not remove unless you know what you are doing.

none /etc/network/interfaces.dynamic.d tmpfs nodev,noexec,nosuid,size=64K 0 0 /dev/sdb1 /mnt auto defaults,nofail,comment=cloudconfig 0 2

Which one is easier option. And how can I do it?

Answer 1

Short answer is that you cannot make "/" (=root partition) bigger. Seem you have a 32GB SDD for fast access and a 3TB HDD for your data. It is up to you to save the data that need speed (e.g. OS) on the SSD and your data that is just big (e.g. data files, mp3, movies, etc.) on your HDD.

Normal setup would be to mount your HDD as /home and leave the rest on the SSD. This assumes that you only install a few programs and have all your data under /home/username/Documents, /home/username/Downloads, /home/username/Music, /home/username/Pictures, /home/username/Video, etc...

Note that in the end it will depend on your setup, e.g. if you use KVM/libvirt as a virtualization solution, your virtual machines (consuming GB of data) may land in /var/lib/libvirt, hence outside of your home directory.