Regarding OS partition and root user

Linux and Unix-Like Ubuntu
1

Dear Concern,

I am new in ubuntu. Is root user disable in ubuntu? Also, is os partition default in ubuntu? I don't find any feature to create customize mount point to install OS.
Below is my current OS partition.

amirislam@blnidapp03:~$ df -h
Filesystem                       Size  Used Avail Use% Mounted on
/dev/mapper/blnidapp03--vg-root   51G  1.2G   48G   3% /
none                             4.0K     0  4.0K   0% /sys/fs/cgroup
udev                             3.9G  4.0K  3.9G   1% /dev
tmpfs                            798M  1.3M  797M   1% /run
none                             5.0M     0  5.0M   0% /run/lock
none                             3.9G     0  3.9G   0% /run/shm
none                             100M     0  100M   0% /run/user
/dev/sda1                        236M   38M  186M  17% /boot

Also procedure to lvm management is similiar to Redhat?

---------- Post updated at 09:39 AM ---------- Previous update was at 09:35 AM ----------

Dear Concern,

Also, please inform me is 51 GB is sufficient for / mount point for below mentioned version of ubuntu?

amirislam@blnidapp03:~$ uname -a
Linux blnidapp03 3.19.0-25-generic #26~14.04.1-Ubuntu SMP Fri Jul 24 21:16:20 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux
2

Good day. From looking at your df output, it would appear as though your hard drive in question has at least 2 partitions.

mirislam@blnidapp03:~$ df -h
Filesystem                       Size  Used Avail Use% Mounted on
/dev/mapper/blnidapp03--vg-root   51G  1.2G   48G   3% /
/dev/sda1                        236M   38M  186M  17% /boot

Basically you have your /boot partition at partition 1 ( /dev/sda1 ) and the other is a dev mapping, which is using LVM. Thus your partition layout would most likely be:

/dev/sda1 = your /boot
/dev/sda5 = extended partition (which can then encapsulate multiple partitions)

This is generally preferable, so you don't hit the maximum 4 primary partitions per hard drive. This can be seen by running: sudo fdisk -l /dev/sda

As for 51 GB, that is the current space allocated to the root (/) partition. This may / may not be enough. It is dependant on your individual preferences for extra packages that you install, if you download alot of media files, ISO's etc.

You may have more space unalloacted / unused in your VG. However, you would need to provide more details on that. Please run the following commands, and paste the output here so people have a better under standing of your particular setup.

sudo vgs
sudo las

More detailed information can be gathered with:

sudo vgdisplay
sudo lvdisplay