How to raise size of working partition under Kubuntu 18

I installed Kubuntu 18 about 3 weeks ago on partition in 28G,
but after installing of docker seems this space is not enough for my root partition

$ df -HT   
Filesystem     Type      Size  Used Avail Use% Mounted on
udev           devtmpfs  4,2G     0  4,2G   0% /dev
tmpfs          tmpfs     828M  1,7M  827M   1% /run
/dev/sdb5      ext4       28G   27G     0 100% /
tmpfs          tmpfs     4,2G  186M  4,0G   5% /dev/shm
tmpfs          tmpfs     5,3M  4,1k  5,3M   1% /run/lock
tmpfs          tmpfs     4,2G     0  4,2G   0% /sys/fs/cgroup
/dev/sdb7      ext4       30G   15G   13G  54% /mnt/_Prior_Kubuntu_18
/dev/sdb8      fuseblk   399G   88G  311G  23% /mnt/_work_sdb8
/dev/sdb1      ext4      347M   91M  235M  28% /boot
/dev/sda6      fuseblk   237G  136G  101G  58% /mnt/Work_sda6
/dev/sda8      fuseblk   628G  606G   22G  97% /mnt/Media_sda8
tmpfs          tmpfs     828M   21k  828M   1% /run/user/1000

My working partition is /dev/sdb5. Also I use /dev/sdb7 for ubuntu installation.
In gparted I see :

I think to raise size of /dev/sdb5 and /dev/sdb7 till 50G and to get disk from /dev/sdb8 .
Can you advice in which(simple and safe) way and using which tools can I make it ?
Is it better to make it from my current Kubuntu 18 or run it live from my usb installation ?



I suggest you to follow up this tutorial:

If you have additional questions do not hesitate to ask.

After some thinking I decide to use another way, which seems more safe.
Besides my “/”, “/boot”, “/swap” partitions I have 1 more addtive partition, which is not used.
I found an info that I can use it for docker, but I need to reinstall my OS.

I opened Kubuntu install wizard and without reinstalling my OS I checked :

  1. I need to select “/” and “/boot” partinions with option to format them.
  2. Also I need to select 1 more partinion, but which type have I select for it?
    When select point for additive partinion I see next options : “/”, “/boot”, “/home”, “/tmp”, “/usr”, “/var”, “/srv”, “/opt”, “/usr/local”?
    Which of them have I to select (with formatting it) to use for docker?
  3. Could you please provide a link how on new installed OS to istall and use docker to keep all its data on this addtive partition ?


I recommend just a “/” and “/boot” partition. Maybe a swap partition, but those aren’t mounted in the filesystem, so you shouldn’t be seeing a “/swap”. Most of the other partition suggestions like /var and /usr/local are ancient historical decisions you no longer need to care about.

Some do like a separate partition for /home so they can encrypt it without encrypting the rest of the drive. I don’t much like a separate /home, I hate running out of space on the partition when I have plenty left in others. And most of the data you fatten up your system with will probably live in /home anyway.

As for docker, you don’t use it to keep data. In fact, it’s usually used for the purpose of not keeping data between container activations, or at least keeping data private to the container (such as a database). What were you planning on using docker for?

I need docker for learning it.

As that is rather risky to resize partitions with live data and I have 2 partitions 28 and 25 GiB
Biggest for “/” and in 25 GiB partition I want to install “/var.”
Both are on the same ssd disk.

When select point for additive partinion I see next options : “/”, “/boot”, “/home”, “/tmp”, “/usr”, “/var”, “/srv”, “/opt”, “/usr/local”?

I selected “/var” as I tried to install docker and I found that /var/lib/docker/ takes 11.1 GiB.
I think that installing “/var” into 25 GiB partition I will not have problems with lack of space.
Installiog linux I have never installed some one of options : “/home”, “/usr”, “/var” into separate partion.
Just want to confirm, no any risk ? If there is what I have to pay attention at installing/working in OS?