I signed up for a free VPS on Ohava - 20GB is what is advertised. When I
logged into the system, df -h showed this:

Filesystem                   Size  Used Avail Use% Mounted on
/dev/mapper/ubuntu--vg-root  6.6G  1.8G  4.6G  28% /
none                         4.0K     0  4.0K   0% /sys/fs/cgroup
udev                         235M  4.0K  235M   1% /dev
tmpfs                         50M  368K   49M   1% /run
none                         5.0M     0  5.0M   0% /run/lock
none                         246M     0  246M   0% /run/shm
none                         100M     0  100M   0% /run/user
/dev/vda1                    236M   68M  156M  31% /boot

I queried to the support group, so they sent me instructions to add 10 more
GB.

df now shows:

Filesystem                   Size  Used Avail Use% Mounted on
/dev/mapper/ubuntu--vg-root   17G  1.8G   14G  12% /
none                         4.0K     0  4.0K   0% /sys/fs/cgroup
udev                         235M  4.0K  235M   1% /dev
tmpfs                         50M  368K   49M   1% /run
none                         5.0M     0  5.0M   0% /run/lock
none                         246M     0  246M   0% /run/shm
none                         100M     0  100M   0% /run/user
/dev/vda1                    236M   68M  156M  31% /boot

The support groups said:


*Our apologies on the confusion. This is a current bug in the machines
being spun up, but we definitely offer (and want to help you get) the full
amount of space. Every instance gets 20GB partitioned to them. There is
some overhead in some of the other partitions of disk space so / won't ever
show the full 20GB, as small parts of the 20GBs are allocated elsewhere. *


*The instructions sent to you are for extending the / partition an
additional 10GB. Since there was already some amount of storage there, the
result after completing the instructions (and the correction to the error
that we made when we originally sent you instructions on expanding the lvm
volume..."sudo lvextend -L+10G /dev/ubuntu-vg/root") should get you as
close as possible to 20GB (~18.75GB) on /root while allowing for the
overhead. *
I get the calculation of disk size issue, so a 20 GB drive is really only
18.63 GB. But shouldn't df show 18.63 GB and not 17 GB? Is the discrepancy
(1.63 GB or 8.75% of the drive) due to formatting the disk and adding
Ubuntu server?

Thanks,

Mark