Disk Partitioning and File System Essentials

​A storage disk can be ​divided into something called partitions A partition is just a piece of ​the disk that you can manage.

• gives you the illusion that you’re physically ​dividing a disk into separate disks. ​

Let’s say you want to have two partitions on a disk.  ​One for a Windows OS and one for Linux OS.

 ​Instead of using two machines to ​use both operating systems….. you can just use one machine and switch ​between the two OSs on boot up. You can also add different file systems ​on different partitions of the same disk. ​Partitions essentially act as ​their own separate sub disks ​but they all use the same physical disk.

One thing to call out is that when you ​format a file system on a partition, ​it becomes a volume. ​Volume and partition are ​sometimes mistakenly used synonymously. ​But we want to make sure that ​you understand this distinction.

• Volume: A format for a filesystem on a partition

The other component of a disk is a partition table.

• Partition table: How the disk is partitioned on an OS

There are two main partition table schemes that are used. ​

• MBR or master boot record
• ​GPT or GUID partition table. These schemes decide how to ​structure the information on partitions

MBR is a traditional partition table ​and it’s mostly used in the Windows OS.

• MBR only lets you have ​volumes sizes of two terabytes or less.
• ​It also uses something called primary partitions. ​You can only have four primary partitions on a disk. ​If you want to add more, you have to take ​a primary partition and make it into ​something known as an extended partition. 
• ​Inside the extended partition, ​you can then make something called a logical partition. ​It’s a little odd to get it first but ​that’s just how the partition table was created. ​
• MBR is an old standard.

GPT is becoming the new standard for disks. ​

• You can have a volume size greater than ​two terabytes and it only has one type of partition. 
• ​You can make as many of them as you want in a disk. 
• ​In an earlier lesson, ​we learned about a new bios standard called UEFI. ​That’s become the default bios for new systems. ​To use UEFI booting, ​your disk has to use the GUID partition table.