Need information

[Robert Heller]

At Thu, 24 Aug 2023 19:09:03 +0530 "Ubuntu user technical support,? not for general discussions" <ubuntu-users at lists.ubuntu.com> wrote:

> 
> Hi,
> 
> In our servers with Ubuntu OS, the  '/' file system is mounted on a device
> mapper as shown below:
> ---
> # df -h
> Filesystem                 Size  Used Avail Use% Mounted on
> devtmpfs                   252G     0  252G   0% /dev
> tmpfs                      252G     0  252G   0% /dev/shm
> tmpfs                      252G   13G  240G   6% /run
> /dev/mapper/live-rw         15G   13G  1.8G  88% /
> --
> 
> Root file system is not mapped to a hard disk. What exactly  is the
> 'dev/mapper/live-rw' device ? Does it mean that the root file system is in
> memory instead on a hard disk ?   Please explain

What do you mean by "servers"?  Are these VPS in the cloud somewhere?

There are any number of possibilities -- we need much more info to answer your 
question.  *One* possibility is LVM.  *I* use LVM on some of my machines:

sauron% df -h
Filesystem                             Size  Used Avail Use% Mounted on
tmpfs                                  769M  2.2M  767M   1% /run
/dev/mapper/sauron-ubuntu_root          50G   42G  5.1G  90% /
tmpfs                                  3.8G   32K  3.8G   1% /dev/shm
tmpfs                                  5.0M  8.0K  5.0M   1% /run/lock
tmpfs                                  3.8G     0  3.8G   0% /run/qemu
/dev/mapper/sauron-www                 9.8G  1.2G  8.1G  13% /var/www
/dev/mapper/sauron-distrocds            79G   68G  7.2G  91% /distrocds
/dev/mapper/sauron-wine                261M  172M   75M  70% /wineC
/dev/mapper/sauron-Stuff                21G   17G  3.6G  83% /Stuff
/dev/mapper/sauron-dvdisos              44G   41G  1.1G  98% /dvdisos
/dev/mapper/sauron-SourceManagementC5  942M  303M  588M  34% /home3/heller/Deepwoods
/dev/md126                             948M  416M  483M  47% /boot
/dev/mapper/sauron-extra                50G   31G   16G  67% /extra
/dev/mapper/sauron-localrepo           868M  1.3M  815M   1% /var/www/localrepo
/dev/mapper/sauron-home                 70G   60G  7.4G  89% /home
/dev/mapper/sauron-pipinbackup         246G  107G  127G  46% /PipinBackup

gollumm1% df -h
Filesystem                     Size  Used Avail Use% Mounted on
udev                           1.9G     0  1.9G   0% /dev
tmpfs                          374M   25M  350M   7% /run
/dev/mapper/Gollum_m1-m1_root   30G  7.2G   21G  26% /
tmpfs                          1.9G     0  1.9G   0% /dev/shm
tmpfs                          5.0M  4.0K  5.0M   1% /run/lock
tmpfs                          1.9G     0  1.9G   0% /sys/fs/cgroup
/dev/nvme0n1p1                 920M   27M  830M   4% /boot
/dev/mapper/Gollum_m1-mp3s      20G   17G  2.6G  87% /mp3s
/dev/mapper/Gollum_m1-scratch   40G   37G 1022M  98% /scratch
/dev/mapper/Gollum_m1-home      37G   17G   18G  49% /home

(LVM is a convientient way of managing disk space with large storage media.)
> 
> 
> Thanks
> Kumar
> 

-- 
Robert Heller             -- Cell: 413-658-7953 GV: 978-633-5364
Deepwoods Software        -- Custom Software Services
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