Welcome back to managing Linux systems. This is the second course in the Linux Foundation Specialization. In this module we want to think about managing disk storage. We use disk to persist information across executions of programs, so it's different than RAM. Ram is volatile, meaning it needs power for data to be saved. Disk is where we permanently store information. By the time you're done with this module, I want you to be able to do several things. This includes partition hard drives into smaller sections that can be formatted. Once you be able to manage the Linux file systems, I want you to be able to mount Linux file systems and lastly, monitor those file systems. Let's start out by thinking about hard drive partitions. Most operating systems, including Linux, allow you to partition a drive into multiple sections, and a partition is a self-contained section within the drive that the operating system treats as a separate storage space. Partitioning drives can help you better organize your data, such as segmenting operating system data from user data, so you may have two partitions. One is where I install the operating system and one is where I store my user data that I want to backup differently. There are two different methods we can use for partitioning our disk. The old method is what's called an MBR master boot record, and this supports up to four primary partitions on a drive and the primary partitions can be split into multiple extended partitions. The newer method is what's called UEFI bootloader, which is an advanced GUID partition table, GPT method for managing partitions which supports up to 128 partitions on a drive. The Linux system boots is going to detect the drives and partitions and assign each one a unique device filename. The invention of removable USB drives, which can be added and removed while the system is running complicates things a little bit. When you add or remove a removable storage device, the /dev name is assigned to it, and it may change each time depending on what devices are connected at that time. These changes can make it difficult for applications to find the same storage device each time. We have the fdisk command. This disk program allows you to create, view, delete, and modify partitions on any drive that uses the MBR method of indexing partitions. An example usage here is fdisk/dev/sdb, and there's lots of common commands I've listed here. The a will make a bootable flag set either you're toggling it on and off, if you will, the d deletes a partition, the n adds a new partition, the p will print the partition table, v will verify the partition table and lastly write will write back your changes to the table and exit. The gdisk command is similar, but it allows you to create, view, delete, modify partitions on any drive that uses the GPT method of indexing partition. You just need to remember if it's using a master boot, then it needs an fdesk, if it's using GPT then its gdesk. An example here is very similar gdisk/dev/sdb. There are common commands here, so d is to delete a partition, n is to add a new partition, p is to print a partition table, v is to verify the partition table, w is to write the district table and exit. A little bit of review here. Partitioning is going to separate our drive into multiple sections. Fdisk is used with the MBR indexing method and gdisk is used with the GPT indexing method. I will see you in the next lesson.
