1 00:00:00,600 --> 00:00:01,620 In this lesson, 2 00:00:01,620 --> 00:00:04,530 we're going to talk about mounting file systems. 3 00:00:04,530 --> 00:00:06,000 After formatting partitions 4 00:00:06,000 --> 00:00:08,160 and logical volumes with file systems, 5 00:00:08,160 --> 00:00:10,800 we need to make those accessible for users. 6 00:00:10,800 --> 00:00:14,190 So we are going to make these file systems available for users 7 00:00:14,190 --> 00:00:16,920 by mounting them into the operating system. 8 00:00:16,920 --> 00:00:19,200 Now, before an operating system can read from 9 00:00:19,200 --> 00:00:21,450 or write to a disk, the file system 10 00:00:21,450 --> 00:00:24,510 on one of those disk partitions has to be mounted. 11 00:00:24,510 --> 00:00:27,390 Since a file system is really just a big array of bytes 12 00:00:27,390 --> 00:00:29,220 typically stored on a partition, 13 00:00:29,220 --> 00:00:32,400 you need to get access to the file system by mounting it. 14 00:00:32,400 --> 00:00:34,680 Now a mount point is an access point 15 00:00:34,680 --> 00:00:36,720 where information is going to be stored on a local 16 00:00:36,720 --> 00:00:38,490 or remote storage device. 17 00:00:38,490 --> 00:00:41,640 That mount point is typically going to be an empty directory 18 00:00:41,640 --> 00:00:44,580 on which a file system is going to be loaded or mounted 19 00:00:44,580 --> 00:00:47,610 to make that file system accessible to users. 20 00:00:47,610 --> 00:00:49,530 The mount command is what we're going to use 21 00:00:49,530 --> 00:00:52,410 to load a file system to a specified directory 22 00:00:52,410 --> 00:00:55,410 so it can be accessible to users and applications. 23 00:00:55,410 --> 00:00:58,680 To do this, we have to specify the device to mount to, 24 00:00:58,680 --> 00:01:00,630 as well as the desired mount point. 25 00:01:00,630 --> 00:01:03,780 The proper way to use the mount command is to type mount, 26 00:01:03,780 --> 00:01:05,129 the options you want to use, 27 00:01:05,129 --> 00:01:06,720 the device name you want to use, 28 00:01:06,720 --> 00:01:08,700 and the mount point you want to use. 29 00:01:08,700 --> 00:01:11,100 You can also specify various mount options 30 00:01:11,100 --> 00:01:12,600 for a file system. 31 00:01:12,600 --> 00:01:15,990 These options are typically included in the fstab file 32 00:01:15,990 --> 00:01:18,480 rather than as a command line argument. 33 00:01:18,480 --> 00:01:21,120 Option auto, for example, is used to specify 34 00:01:21,120 --> 00:01:24,330 that the device has to be mounted automatically. 35 00:01:24,330 --> 00:01:26,160 Noauto is going to be used to specify 36 00:01:26,160 --> 00:01:29,070 that the device should not be mounted automatically. 37 00:01:29,070 --> 00:01:31,320 Nouser is going to be used to specify 38 00:01:31,320 --> 00:01:34,710 that only the root user can mount a device or file system. 39 00:01:34,710 --> 00:01:36,690 And user is used to specify 40 00:01:36,690 --> 00:01:39,990 that all users can mount a device or file system. 41 00:01:39,990 --> 00:01:43,050 Exec is going to allow binaries in a file system 42 00:01:43,050 --> 00:01:44,250 to be executed, 43 00:01:44,250 --> 00:01:46,950 whereas noexec is going to be used to prevent binaries 44 00:01:46,950 --> 00:01:49,860 in a file system from being executed. 45 00:01:49,860 --> 00:01:53,460 Ro is going to be used to mount a file system as read only, 46 00:01:53,460 --> 00:01:56,220 whereas rw is used to mount that file system 47 00:01:56,220 --> 00:01:58,560 as a read or write partition. 48 00:01:58,560 --> 00:02:00,243 Sync is going to be used to specify 49 00:02:00,243 --> 00:02:02,040 that input and output operations 50 00:02:02,040 --> 00:02:05,400 in the file system should be done synchronously. 51 00:02:05,400 --> 00:02:07,980 Async, on the other hand, is going to be used to specify 52 00:02:07,980 --> 00:02:09,720 that the input and output operations 53 00:02:09,720 --> 00:02:13,350 in that file system can be done asynchronously. 54 00:02:13,350 --> 00:02:15,540 I know I just mentioned a lot of options there, 55 00:02:15,540 --> 00:02:16,890 and one of the things I mentioned 56 00:02:16,890 --> 00:02:19,140 was a binary being executed. 57 00:02:19,140 --> 00:02:20,790 Now you may not know what a binary is, 58 00:02:20,790 --> 00:02:22,590 so let me cover that real quick. 59 00:02:22,590 --> 00:02:25,170 A binary is source code that has been compiled 60 00:02:25,170 --> 00:02:27,030 into an executable program 61 00:02:27,030 --> 00:02:28,320 or otherwise assembled 62 00:02:28,320 --> 00:02:30,930 so it can be readable by the computer system. 63 00:02:30,930 --> 00:02:32,070 In addition to this, 64 00:02:32,070 --> 00:02:34,320 binaries can also be things like pictures, 65 00:02:34,320 --> 00:02:37,110 word-processing files, or spreadsheet files, 66 00:02:37,110 --> 00:02:38,730 essentially anything that is not 67 00:02:38,730 --> 00:02:41,100 a standard text readable file. 68 00:02:41,100 --> 00:02:42,990 Now after you're done using the file system, 69 00:02:42,990 --> 00:02:45,690 you may choose to unmount that file system. 70 00:02:45,690 --> 00:02:47,550 And this means it'll be disassociated 71 00:02:47,550 --> 00:02:50,310 from the directory by unloading or unmounting it 72 00:02:50,310 --> 00:02:52,230 so it's no longer going to be used. 73 00:02:52,230 --> 00:02:55,530 To do this, we're going to use the umount command. 74 00:02:55,530 --> 00:02:58,200 The umount command stands for unmount. 75 00:02:58,200 --> 00:03:00,180 In order to unmount a file system, 76 00:03:00,180 --> 00:03:02,280 it has to not be in use currently. 77 00:03:02,280 --> 00:03:04,350 That means that you can't have any files 78 00:03:04,350 --> 00:03:07,260 from that file system currently open in some application 79 00:03:07,260 --> 00:03:09,000 like a word-processing program 80 00:03:09,000 --> 00:03:11,460 or a spreadsheet or something like that. 81 00:03:11,460 --> 00:03:14,820 The proper way to use the umount command is to enter umount, 82 00:03:14,820 --> 00:03:16,860 the options, and the mount point. 83 00:03:16,860 --> 00:03:19,410 There's also some common options for you umount, 84 00:03:19,410 --> 00:03:22,380 things like -f, which will force a file system 85 00:03:22,380 --> 00:03:25,230 to be unmounted despite any detected issues. 86 00:03:25,230 --> 00:03:27,420 Be very careful using this one. 87 00:03:27,420 --> 00:03:29,670 There's another option known as -l. 88 00:03:29,670 --> 00:03:31,800 This is used to perform a lazy unmount, 89 00:03:31,800 --> 00:03:34,410 in which the file system is detached from the hierarchy, 90 00:03:34,410 --> 00:03:37,290 but references to that file system are not cleaned up 91 00:03:37,290 --> 00:03:39,990 until the file system is no longer being used. 92 00:03:39,990 --> 00:03:43,140 We can also use -R, which recursively unmount 93 00:03:43,140 --> 00:03:45,210 the specified directory's mount points. 94 00:03:45,210 --> 00:03:48,330 We can also use -t and the file system type 95 00:03:48,330 --> 00:03:50,400 if we want to unmount only the file system types 96 00:03:50,400 --> 00:03:53,010 that are specified like all FAT partitions 97 00:03:53,010 --> 00:03:55,230 or all Ext2 partitions. 98 00:03:55,230 --> 00:03:58,170 We can also use -O with some mount options 99 00:03:58,170 --> 00:04:00,240 to unmount only the file systems that are mattered 100 00:04:00,240 --> 00:04:05,160 with the specified options inside the /etc/fstab file. 101 00:04:05,160 --> 00:04:09,000 Or we can type -fake to test the unmounting procedure 102 00:04:09,000 --> 00:04:11,730 without actually unmounting the file system. 103 00:04:11,730 --> 00:04:14,160 Remember, mounting of the file system occurs 104 00:04:14,160 --> 00:04:16,140 during the startup process normally, 105 00:04:16,140 --> 00:04:21,060 and it's managed by the /etc/fstab configuration file. 106 00:04:21,060 --> 00:04:22,860 An easy way to remember this is that, 107 00:04:22,860 --> 00:04:25,830 fstab stands for file system table. 108 00:04:25,830 --> 00:04:27,600 And it's a list of all the file systems 109 00:04:27,600 --> 00:04:28,920 that need to be mounted, 110 00:04:28,920 --> 00:04:30,270 their designated mount points, 111 00:04:30,270 --> 00:04:32,250 and any other options that might be needed 112 00:04:32,250 --> 00:04:34,470 for specific file systems. 113 00:04:34,470 --> 00:04:36,840 Another method of mounting a file system is to use 114 00:04:36,840 --> 00:04:39,210 the systemd or system daemon. 115 00:04:39,210 --> 00:04:42,330 The systemd.mount can be used to create a new mount unit 116 00:04:42,330 --> 00:04:44,160 to mount this file system. 117 00:04:44,160 --> 00:04:46,830 To set this up, you need to create a text file located 118 00:04:46,830 --> 00:04:50,850 in the /etc/systemd/system directory 119 00:04:50,850 --> 00:04:53,550 and name it as something.mount. 120 00:04:53,550 --> 00:04:55,200 For example, here, I'm going to create 121 00:04:55,200 --> 00:04:59,862 a text file called /etc/systemd/system 122 00:04:59,862 --> 00:05:03,492 /var-lib-docker.mount. 123 00:05:03,492 --> 00:05:05,220 And this is going to be used to mount a specific disk 124 00:05:05,220 --> 00:05:09,870 and its UUID to the /var/lib/docker directory 125 00:05:09,870 --> 00:05:11,310 as a mount point. 126 00:05:11,310 --> 00:05:14,280 I've done this using the btrfs file system 127 00:05:14,280 --> 00:05:15,990 and the default options. 128 00:05:15,990 --> 00:05:18,720 To enable this, I'm going to use systemctl 129 00:05:18,720 --> 00:05:23,580 and enter systemctl enable var-lib-docker.mount 130 00:05:23,580 --> 00:05:25,020 at my Command Prompt. 131 00:05:25,020 --> 00:05:26,460 When I reboot my system, 132 00:05:26,460 --> 00:05:28,200 this new mount point is going to be created, 133 00:05:28,200 --> 00:05:30,360 and the disk is going to be mounted to it. 134 00:05:30,360 --> 00:05:31,650 The final thing I want to discuss 135 00:05:31,650 --> 00:05:34,200 in this lesson concerning file systems is the concept 136 00:05:34,200 --> 00:05:38,010 of FUSE, which is the Filesystem in USErspace. 137 00:05:38,010 --> 00:05:40,500 FUSE is a software interface in Linux systems 138 00:05:40,500 --> 00:05:43,650 that lets non-privileged users create their own file systems 139 00:05:43,650 --> 00:05:46,410 without editing the underlying kernel code. 140 00:05:46,410 --> 00:05:48,300 FUSE was originally developed and designed 141 00:05:48,300 --> 00:05:49,890 as a virtual file system 142 00:05:49,890 --> 00:05:52,290 that allows you to specify how read, write, 143 00:05:52,290 --> 00:05:55,140 and stat requests can be made to a file system, 144 00:05:55,140 --> 00:05:58,140 as well as how to mount this new file system you'd create. 145 00:05:58,140 --> 00:06:00,810 FUSE is commonly used to create virtual file systems 146 00:06:00,810 --> 00:06:02,910 that are detached from the underlying physical media 147 00:06:02,910 --> 00:06:04,320 or drives themself. 148 00:06:04,320 --> 00:06:06,810 And this allows them to act as sort of a translation 149 00:06:06,810 --> 00:06:09,510 between different file system types as needed. 150 00:06:09,510 --> 00:06:11,520 For example, if you need to be able to read 151 00:06:11,520 --> 00:06:13,800 or write to an NTFS-based volume 152 00:06:13,800 --> 00:06:15,750 but your system doesn't support it natively, 153 00:06:15,750 --> 00:06:18,080 you could write a translation program using the Filesystem 154 00:06:18,080 --> 00:06:21,210 in USErspace to provide you with this capability. 155 00:06:21,210 --> 00:06:23,220 Other common uses of FUSE is to allow 156 00:06:23,220 --> 00:06:25,350 a local Linux operating system to interact 157 00:06:25,350 --> 00:06:27,420 with cloud-based file storage systems 158 00:06:27,420 --> 00:06:31,230 like Amazon's S3 Buckets or Microsoft Azure Blobs. 159 00:06:31,230 --> 00:06:33,480 As you can guess, FUSE is really useful 160 00:06:33,480 --> 00:06:34,440 to be able to read and write 161 00:06:34,440 --> 00:06:36,330 to all sorts of different file systems 162 00:06:36,330 --> 00:06:37,650 that you can then mount easily 163 00:06:37,650 --> 00:06:39,550 inside of your Linux operating system.