In order to work with partitions,
first thing you need to understand is this layout.
So how does it work?
Well, from the UEFI, which is the firmware that
is used for booting your computer,
the boot disk is assigned.
And on the boot disk, the first megabyte
is reserved for metadata.
Metadata is data that is required for booting
information about your system.
Historically, the master boot record, or MBR,
is in the first 512-byte sector and was just used for booting.
But nowadays, the firmware addresses the UEFI boot
partition, and the MBR only contains the protective MBR
if at all.
Sometimes it's completely empty.
The protective MBR may be there for legacy applications,
and it indicates that the disk is in use.
Now, starting the second sector, which
is from byte 513 up to 1024, the partition table is stored.
And each partition entry needs a total of 120 bytes.
And with a total of 128 partitions that can be created,
you need a total of 32 sectors, which
is 16 kibibytes for storing the partition table.
Partitions are the primary entities to allocate disk space.
And each rail system must have partitions,
as the UEFI boot partition is required in the boot procedure.
And this UEFI boot partition is a partition
that is readable from all operating systems
and which contains essential system information.
Even if your system uses a logical volume manager,
partitions are still required.
Partitions are old.
They have been introduced with the introduction of the PC
in 1981.
On each partition, a file system is created
to organize file storage.
And on Linux servers, it is common to work
with multiple partitions to separate
different types of files, or multiple partitions
and logical volumes, because logical volumes add
a lot of flexibility on top of the partitions.
In most cases, your partitions are created
while installing a server.
And different storage areas are mounted,
like boot EFI for your firmware, slash boot,
which contains your kernel, slash for your root file
system, and optional mounts like home and var.
And there is normally also some swap space.
If additional disk devices are added later,
or if virtual disks are increased in size,
it might be required to manage partitions.
And regardless, managing storage for RHCSA
is a very important topic.
In the next lessons, you'll learn all about it.