1 00:00:06,639 --> 00:00:08,929 Linux is very flexible with regard to storage. 2 00:00:09,810 --> 00:00:15,919 So let's say the square box is your computer and in your computer there's a hard disk. 3 00:00:16,559 --> 00:00:18,359 The circle represents your hard disk. 4 00:00:19,100 --> 00:00:23,690 Then the minimal thing that you need to do in your hard disk is to create partitions. 5 00:00:25,149 --> 00:00:30,550 These partitions are for logically distinguishing the files that you are going to put on your hard disk. 6 00:00:31,730 --> 00:00:34,789 Partitions, however, are relatively inflexible. 7 00:00:35,429 --> 00:00:40,020 And that is why inside the partitions you can go for a different solution. 8 00:00:40,700 --> 00:00:42,219 And that is the logical volume. 9 00:00:42,840 --> 00:00:47,965 So what would you do? Well, you would use the partition which is then 10 00:00:47,965 --> 00:00:53,090 known as physical volume, and put it in kind of a storage cloud. 11 00:00:53,619 --> 00:00:55,240 That is what you call the volume group. 12 00:00:56,039 --> 00:01:00,875 And from this volume group you can define your logical 13 00:01:00,875 --> 00:01:05,709 volumes like LV1 and LV2 and LV3 and so on. 14 00:01:06,209 --> 00:01:12,579 Where the advantage of these logical volumes is that you introduce flexibility with regard to your storage. 15 00:01:13,340 --> 00:01:16,780 One important feature is that you can resize them very easily. 16 00:01:17,500 --> 00:01:20,500 So partitions and logical volumes are very important in Linux. 17 00:01:21,609 --> 00:01:24,609 But there's also an option to work with external storage. 18 00:01:25,689 --> 00:01:32,260 You can use SAN or nas, and on the SAN or NAS you can have multiple disks available 19 00:01:32,260 --> 00:01:38,830 and you can make them accessible from your Linux server by using storage protocols like ISCSI or Fibre 20 00:01:38,829 --> 00:01:45,400 Channel. And the result is that you will see them as a disk on your computer. 21 00:01:45,900 --> 00:01:51,719 And the next question is, how are you going to work with them? Well, the first thing to do 22 00:01:51,719 --> 00:01:57,539 is lsblk. LSBLK is listing block devices and that allows you to see all of your storage devices. 23 00:01:59,200 --> 00:02:03,939 Okay, so let's have a look at the common Linux block device overview. 24 00:02:04,579 --> 00:02:10,020 So there is DEV sda, which is the first SCSI or SATA hard disk. 25 00:02:10,580 --> 00:02:14,245 Dev SDB would be the second disk. South Dakota stands for 26 00:02:14,245 --> 00:02:17,909 SCSI disk, and A and B is the disk names. 27 00:02:18,469 --> 00:02:22,810 We have dev vda, which is commonly used for a KVM hard 28 00:02:22,810 --> 00:02:27,150 disk, and dev nvme0, n1, which is your first nvme hard disk. 29 00:02:27,830 --> 00:02:31,720 Normally the first hard disk is a, the second hard disk 30 00:02:31,720 --> 00:02:35,610 is b, and so on. But in nvme you use numbering. 31 00:02:36,110 --> 00:02:40,465 So nvme0 is for bus 0 and n1 is node 1, which is 32 00:02:40,465 --> 00:02:44,819 the first disk, and n2 will be the second disk, and so on. 33 00:02:45,560 --> 00:02:52,199 Also commonly seen is dev sr0, which is what you use for an optical drive. 34 00:02:52,979 --> 00:02:58,069 How can we verify all of that? That would be the LSBOK command. Let me 35 00:02:58,069 --> 00:03:03,159 show you the LSBOK command for an overview of what is on a system. 36 00:03:05,219 --> 00:03:08,620 Sudo lsblk showing my block devices. 37 00:03:09,639 --> 00:03:13,780 What I've got here is an SR 0 and an NVME 0 and 1. 38 00:03:14,560 --> 00:03:19,415 Now, on this NVME 0 and 1, we have a couple of partitions and there is LVM 39 00:03:19,415 --> 00:03:24,270 logical volumes as well. In the next couple of lessons, you'll learn how to work with these.