LFS201 - Chapter 16 Discussion // Questions // Banter

heiko_s

Referring to chapter 16 - Linux Filesystems and the VFS, I created a bash script to run the Demo: Filesystems

The script creates a 512M junk file filled with zeros, then creates a xfs file system inside, then mounts it. It then prints some info, unmounts and deletes the file.

#!/bin/bash
# xfs exercise

# Create file "junk" filled with zeros (512 Mbyte)
cmd="dd if=/dev/zero of=junk bs=1M count=512"
echo "$cmd"
${cmd}
echo -e "\n"

# Create a xfs file system inside junk
cmd="sudo mkfs.xfs junk"
echo "$cmd"
${cmd}
echo -e "\n"

# Mount the xfs file system to /mnt
# Note: there is no need for the -o loop option as Linux can figure out the
# loop file system by itself :-)
cmd="sudo mount junk /mnt"
echo "$cmd"
${cmd}
echo -e"\n"

# See if it's mounted
cmd="df"
echo "$cmd"
${cmd}
echo -e "\n"

# Here the output line relating to the xfs file system:
#/dev/loop0                 518816    30092    488724   6% /mnt

# Let's check if it's really a xfs file system:
cmd="grep xfs /proc/mounts"
echo "$cmd"
${cmd}
echo -e "\n"

# We could now create or copy content to the xfs file system, but we 
# unmount
cmd="sudo umount /mnt"
echo "$cmd"
${cmd}
echo -e "\n"

# and delete the file
cmd="rm junk"
echo "$cmd"
${cmd}

Perhaps you find it useful to play around or file the commands.

luisviveropena

Hi @heiko_s , that's great! Perhaps you could share/demonstrate it with the participants, when we get there.

Many regards,
Luis.

coop

We've tended not to apply many such scripts for exercises because I have done it in other courses and found students would run the scripts and think they understand the subject, but not (at their fingertips, or easily researched) be able to do the same steps on their own. (i.e., learning is more difficult but more solid when you do things. I did not look in detail at the script you supplied but it looks quite nice and I'm sure some students will find it quite useful. However, I encourage them to study it, and reproduce many of the steps by hand!

BTW, I'm not sure if all distributions have xfs and its tools installed by default. RHEL/CentOS/Fedora do as they have it as a default filesystem, but I'm not sure about Ubuntu or OpenSUSE. -- I just checked xfs-tools is installed on Ubuntu 20.04 and the kernel knows xfs, so OK there.