1 00:00:00,810 --> 00:00:01,830 In this lesson, 2 00:00:01,830 --> 00:00:04,590 we're going to discuss how to manage file systems 3 00:00:04,590 --> 00:00:06,180 including all the tools available 4 00:00:06,180 --> 00:00:09,720 in the Linux environment to accomplish practical tasks. 5 00:00:09,720 --> 00:00:11,280 Now to manage our file systems, 6 00:00:11,280 --> 00:00:14,280 we're going to use lots of different files and configurations. 7 00:00:14,280 --> 00:00:15,600 For example, we're going to start 8 00:00:15,600 --> 00:00:19,230 by discussing the /etc/mtab file. 9 00:00:19,230 --> 00:00:20,610 This file is very similar 10 00:00:20,610 --> 00:00:23,190 to the /proc/mounts file 11 00:00:23,190 --> 00:00:24,630 in the way it reports the status 12 00:00:24,630 --> 00:00:26,760 of currently mounted file systems. 13 00:00:26,760 --> 00:00:31,050 However, the /proc/mounts file is typically more accurate 14 00:00:31,050 --> 00:00:32,670 and includes more up to date information 15 00:00:32,670 --> 00:00:37,670 about the file systems than does the /etc/mtab file. 16 00:00:37,830 --> 00:00:42,090 The /proc/partitions file is part of the virtual file system 17 00:00:42,090 --> 00:00:44,970 that contains information about each and every partition 18 00:00:44,970 --> 00:00:47,130 that is currently attached to the system. 19 00:00:47,130 --> 00:00:51,510 The format of the /proc/partition file contains columns 20 00:00:51,510 --> 00:00:54,120 including things like major, minor, 21 00:00:54,120 --> 00:00:56,160 number of blocks and name. 22 00:00:56,160 --> 00:00:58,770 The major column represents the class of device, 23 00:00:58,770 --> 00:01:01,260 so that it can be mapped to an appropriate driver. 24 00:01:01,260 --> 00:01:04,860 The minor column separates partitions into physical devices, 25 00:01:04,860 --> 00:01:06,900 while the number of blocks column refers 26 00:01:06,900 --> 00:01:08,280 to the number of physical blocks 27 00:01:08,280 --> 00:01:09,990 that the partition takes up. 28 00:01:09,990 --> 00:01:13,470 And the name column refers to the name of the partition. 29 00:01:13,470 --> 00:01:16,920 Another command we can look at is the LS block column. 30 00:01:16,920 --> 00:01:19,740 Now lsblk is the command that's going to be used 31 00:01:19,740 --> 00:01:22,890 to display all the information about block storage devices 32 00:01:22,890 --> 00:01:25,560 that are currently available on the given system. 33 00:01:25,560 --> 00:01:27,090 The output is going to be displayed 34 00:01:27,090 --> 00:01:29,730 in a tree-like format with each physical disk 35 00:01:29,730 --> 00:01:31,830 at the top of the tree and each partition 36 00:01:31,830 --> 00:01:35,010 or logical volume branching off from that device. 37 00:01:35,010 --> 00:01:37,950 The information displayed here is going to include the names, 38 00:01:37,950 --> 00:01:41,370 the major and minor numbers, the size, the device type, 39 00:01:41,370 --> 00:01:42,630 and the mount point. 40 00:01:42,630 --> 00:01:46,680 The proper way to use this command is to type lsblk, 41 00:01:46,680 --> 00:01:49,050 the options, and then the device name. 42 00:01:49,050 --> 00:01:50,730 There are lots of options in this command 43 00:01:50,730 --> 00:01:53,310 that you can choose from depending on your needs. 44 00:01:53,310 --> 00:01:55,860 For example, if you use the -a option, 45 00:01:55,860 --> 00:01:57,510 it's going to list out empty devices, 46 00:01:57,510 --> 00:02:00,150 as well as devices that have files on them. 47 00:02:00,150 --> 00:02:01,830 If you use the -r option, 48 00:02:01,830 --> 00:02:03,900 the device list is going to exclude devices 49 00:02:03,900 --> 00:02:05,490 from the output that you provide 50 00:02:05,490 --> 00:02:08,729 as a list of comma separated, major device numbers. 51 00:02:08,729 --> 00:02:10,350 If you use the -f option, 52 00:02:10,350 --> 00:02:12,960 it's going to display additional system information. 53 00:02:12,960 --> 00:02:14,880 Whereas if you use the -l option, 54 00:02:14,880 --> 00:02:17,520 it's going to display your results in a list format. 55 00:02:17,520 --> 00:02:20,040 And finally, if you use the -m option, 56 00:02:20,040 --> 00:02:21,720 it's going to display permission information 57 00:02:21,720 --> 00:02:23,610 for all of your devices. 58 00:02:23,610 --> 00:02:26,370 Another command we can look at is the block ID 59 00:02:26,370 --> 00:02:28,890 or blkid command. 60 00:02:28,890 --> 00:02:32,100 This offers similar functionality to lsblk, 61 00:02:32,100 --> 00:02:34,800 but it simply prints out each block device 62 00:02:34,800 --> 00:02:38,010 in a flat format and includes some additional information 63 00:02:38,010 --> 00:02:40,350 like the device in partitioning UUID 64 00:02:40,350 --> 00:02:42,150 and the file system type. 65 00:02:42,150 --> 00:02:46,920 However, normally I like to use it as lsblk-f 66 00:02:46,920 --> 00:02:48,690 if you want this type of information 67 00:02:48,690 --> 00:02:51,300 instead of using blkid, 68 00:02:51,300 --> 00:02:54,060 but if you want to use blkid, you can do that 69 00:02:54,060 --> 00:02:58,710 by entering in blkid, the options, and the device name. 70 00:02:58,710 --> 00:03:01,590 Now, when it comes to managing file systems and partitions, 71 00:03:01,590 --> 00:03:03,540 some tools are designed to only work 72 00:03:03,540 --> 00:03:06,180 with specific file system types like FAT 73 00:03:06,180 --> 00:03:10,950 or EXT or NTFS or XFS or something like that. 74 00:03:10,950 --> 00:03:13,170 Now, some of these can work with multiple types 75 00:03:13,170 --> 00:03:16,470 or all types, but some specific tools work better 76 00:03:16,470 --> 00:03:18,450 for specific file systems. 77 00:03:18,450 --> 00:03:20,730 If you're going to work with the EXT file system, 78 00:03:20,730 --> 00:03:22,470 which is the default on Linux, 79 00:03:22,470 --> 00:03:24,180 there are several tools that you can use 80 00:03:24,180 --> 00:03:27,750 on essentially any generation of the EXT file system type, 81 00:03:27,750 --> 00:03:30,900 whether it's ext2, three, or four. 82 00:03:30,900 --> 00:03:32,670 Some of the most common and useful tools 83 00:03:32,670 --> 00:03:36,965 for managing EXT file systems include e2fsck, 84 00:03:36,965 --> 00:03:40,983 resize2fs, tune2fs, and dumpe2fs. 85 00:03:42,300 --> 00:03:45,060 At any times, a file system error can occur 86 00:03:45,060 --> 00:03:47,310 due to a power failure, a hardware failure, 87 00:03:47,310 --> 00:03:49,500 or an improper shutdown of your system. 88 00:03:49,500 --> 00:03:53,370 If this happens, you're going to use the fsck command. 89 00:03:53,370 --> 00:03:55,860 Now the fsck command is going to be used to check 90 00:03:55,860 --> 00:03:59,010 for the correctness and validity of a file system. 91 00:03:59,010 --> 00:04:01,830 Most systems automatically run the fsck command 92 00:04:01,830 --> 00:04:03,750 at boot time, so that any errors 93 00:04:03,750 --> 00:04:06,300 if they're found, can be detected and corrected 94 00:04:06,300 --> 00:04:08,160 before the system is used. 95 00:04:08,160 --> 00:04:10,170 A file system must be unmounted 96 00:04:10,170 --> 00:04:12,480 before it can be scanned with fsck 97 00:04:12,480 --> 00:04:14,580 to prevent damage to the file system. 98 00:04:14,580 --> 00:04:18,570 To run fsck, you're going to type fsck, the options, 99 00:04:18,570 --> 00:04:20,850 and the device or file system name. 100 00:04:20,850 --> 00:04:22,860 Sometimes a repair is going to be required 101 00:04:22,860 --> 00:04:25,710 in order to mount or modify a file system. 102 00:04:25,710 --> 00:04:27,540 Even if a check does not report any damage 103 00:04:27,540 --> 00:04:28,680 to the file system, 104 00:04:28,680 --> 00:04:30,780 it might still consider it damaged internally 105 00:04:30,780 --> 00:04:32,460 and require a repair. 106 00:04:32,460 --> 00:04:35,550 You can always use fsck-r 107 00:04:35,550 --> 00:04:38,880 and the device or file system name to repair a file system. 108 00:04:38,880 --> 00:04:41,100 However, this option should not be used 109 00:04:41,100 --> 00:04:44,520 when checking multiple file systems simultaneously. 110 00:04:44,520 --> 00:04:45,930 If you're a system administrator 111 00:04:45,930 --> 00:04:47,848 and you're working on a Linux system, 112 00:04:47,848 --> 00:04:50,040 resizing or growing a file system 113 00:04:50,040 --> 00:04:52,110 can be a challenging task for you. 114 00:04:52,110 --> 00:04:54,300 You're going to need to resize an existing partition 115 00:04:54,300 --> 00:04:57,000 when your partition gets full and you need more space. 116 00:04:57,000 --> 00:05:00,930 In that case, you can use something like resize2fs. 117 00:05:00,930 --> 00:05:03,000 This utility will allow you to increase 118 00:05:03,000 --> 00:05:05,700 or decrease a file system size. 119 00:05:05,700 --> 00:05:09,630 The resize2fs command allows you to resize ext2, 120 00:05:09,630 --> 00:05:12,900 ext3, or ext4 file systems. 121 00:05:12,900 --> 00:05:14,100 It can be used to enlarge 122 00:05:14,100 --> 00:05:17,910 or shrink an unmounted file system locate on a device. 123 00:05:17,910 --> 00:05:20,250 If the file system is mounted, it can be used 124 00:05:20,250 --> 00:05:22,500 to expand the size of the mounted file system, 125 00:05:22,500 --> 00:05:25,650 assuming the kernal supports online resizing. 126 00:05:25,650 --> 00:05:28,650 The size parameter is going to specify the requested new size 127 00:05:28,650 --> 00:05:30,210 of that file system. 128 00:05:30,210 --> 00:05:33,660 If no units are specified, the units of the size perimeter 129 00:05:33,660 --> 00:05:35,850 should be the file system block size 130 00:05:35,850 --> 00:05:37,440 for the entire file system, 131 00:05:37,440 --> 00:05:39,330 and it will use that by default. 132 00:05:39,330 --> 00:05:41,700 The size of the file system may never be larger 133 00:05:41,700 --> 00:05:43,620 than the size of the partition though. 134 00:05:43,620 --> 00:05:45,810 If the size perimeter is not specified, 135 00:05:45,810 --> 00:05:47,910 it's going to default to the size of the partition 136 00:05:47,910 --> 00:05:50,130 and fill up all remaining space. 137 00:05:50,130 --> 00:05:51,600 If you want to use this command, 138 00:05:51,600 --> 00:05:54,870 simply type resize2fs, the options, 139 00:05:54,870 --> 00:05:56,610 and the device or file system name 140 00:05:56,610 --> 00:05:59,370 and the desired size to be able to run this command 141 00:05:59,370 --> 00:06:01,380 and resize your partition. 142 00:06:01,380 --> 00:06:04,380 The next one we're going to talk about is tune2fs. 143 00:06:04,380 --> 00:06:06,810 This command is one of the advanced Linux commands 144 00:06:06,810 --> 00:06:09,330 that allows you to adjust various tuneable parameters 145 00:06:09,330 --> 00:06:12,630 to the ext2 and ext3 file systems. 146 00:06:12,630 --> 00:06:15,690 Tuneable parameters enable you to remove reserve blocks, 147 00:06:15,690 --> 00:06:17,340 alter reserve block counts, 148 00:06:17,340 --> 00:06:19,710 specify the number of mounts between checks, 149 00:06:19,710 --> 00:06:22,830 specify the time intervals between checks, and more. 150 00:06:22,830 --> 00:06:25,680 Naturally, it also helps you confirm the existing parameters 151 00:06:25,680 --> 00:06:27,720 configured for your file systems. 152 00:06:27,720 --> 00:06:30,540 You can also use tune2fs to add a journal 153 00:06:30,540 --> 00:06:34,230 to an existing ext2 or ext3 file system. 154 00:06:34,230 --> 00:06:36,090 If the file system is already mounted, 155 00:06:36,090 --> 00:06:37,200 the journal will be visible 156 00:06:37,200 --> 00:06:39,780 in the root directory of that file system. 157 00:06:39,780 --> 00:06:41,610 If the file system is not mounted, 158 00:06:41,610 --> 00:06:43,200 the journal will be hidden. 159 00:06:43,200 --> 00:06:45,300 To run the tune2fs command, 160 00:06:45,300 --> 00:06:48,090 you need to enter tune2fs, the options, 161 00:06:48,090 --> 00:06:50,100 and the device or file system name. 162 00:06:50,100 --> 00:06:53,220 The tune2fs command has various different options 163 00:06:53,220 --> 00:06:56,910 including -j, which is used as an ext3 journal 164 00:06:56,910 --> 00:06:58,710 to an existing file system. 165 00:06:58,710 --> 00:07:00,810 If you use -I, it's going to be used 166 00:07:00,810 --> 00:07:02,760 to specify the maximum time interval 167 00:07:02,760 --> 00:07:04,350 between file system checks, 168 00:07:04,350 --> 00:07:06,270 and you can give it the parameter of days, 169 00:07:06,270 --> 00:07:10,110 months or weeks using d, m, or w. 170 00:07:10,110 --> 00:07:13,050 If you use -c and the maximum mounts count, 171 00:07:13,050 --> 00:07:15,720 you can use this to specify the maximum number of mounts 172 00:07:15,720 --> 00:07:17,760 between file system checks. 173 00:07:17,760 --> 00:07:21,150 If you use the option -C and the mount count, 174 00:07:21,150 --> 00:07:23,250 it's going to be used to specify the number of times 175 00:07:23,250 --> 00:07:25,410 the file system can be mounted. 176 00:07:25,410 --> 00:07:28,710 If you use the option -r, reserve block counts, 177 00:07:28,710 --> 00:07:30,450 it's going to be used to specify the number 178 00:07:30,450 --> 00:07:32,520 of reserved file system blocks. 179 00:07:32,520 --> 00:07:35,580 If you use the option -e and the word continue, 180 00:07:35,580 --> 00:07:38,700 remountro, or panic, you're going to be able to specify 181 00:07:38,700 --> 00:07:40,470 the behavior of the kernel code, 182 00:07:40,470 --> 00:07:41,672 whether the file system should continue 183 00:07:41,672 --> 00:07:43,380 with normal execution, 184 00:07:43,380 --> 00:07:44,498 whether it should remount the file system 185 00:07:44,498 --> 00:07:46,080 in read-only mode, 186 00:07:46,080 --> 00:07:48,540 or whether it should cause a kernel panic 187 00:07:48,540 --> 00:07:50,550 whenever an error is detected. 188 00:07:50,550 --> 00:07:52,470 If you use the option -l, 189 00:07:52,470 --> 00:07:54,000 it's going to be used to list the contents 190 00:07:54,000 --> 00:07:56,430 within the superblock of the file system. 191 00:07:56,430 --> 00:08:00,720 And finally, if you use the option -u with the UUID, 192 00:08:00,720 --> 00:08:03,630 you can specify the UUID for the file system 193 00:08:03,630 --> 00:08:05,340 that you want set. 194 00:08:05,340 --> 00:08:08,700 A file system superblock is something that contains metadata 195 00:08:08,700 --> 00:08:11,550 about the file system including its size, 196 00:08:11,550 --> 00:08:13,530 its type, and its status. 197 00:08:13,530 --> 00:08:14,940 The superblock is critical 198 00:08:14,940 --> 00:08:17,040 to the function of the file system. 199 00:08:17,040 --> 00:08:19,650 If it becomes corrupted, you're going to be unable 200 00:08:19,650 --> 00:08:22,140 to mount and work with that file system. 201 00:08:22,140 --> 00:08:25,020 So, you need to use a tool like fsck 202 00:08:25,020 --> 00:08:28,110 to repair the superblock if it becomes corrupted. 203 00:08:28,110 --> 00:08:31,860 Another command that we need to talk about is dumpe2fs. 204 00:08:31,860 --> 00:08:35,010 Now dumpe2fs is using a Linux system 205 00:08:35,010 --> 00:08:39,870 that allows you to dump the ext2, ext3, or ext4 data. 206 00:08:39,870 --> 00:08:41,460 It'll actually print the superblock 207 00:08:41,460 --> 00:08:44,610 and the block group information for your selected device. 208 00:08:44,610 --> 00:08:46,260 This can be useful when you're troubleshooting 209 00:08:46,260 --> 00:08:47,880 a faulty file system. 210 00:08:47,880 --> 00:08:51,660 To use it, just type dumpe2fs, the options, 211 00:08:51,660 --> 00:08:53,940 and the device or file system name. 212 00:08:53,940 --> 00:08:57,360 As you do this, the dumpe2fs command is going to have 213 00:08:57,360 --> 00:08:58,920 a lot of different options. 214 00:08:58,920 --> 00:09:01,320 For example, if you use -x, 215 00:09:01,320 --> 00:09:02,970 it's going to print a detailed report 216 00:09:02,970 --> 00:09:05,430 about block numbers in the file system. 217 00:09:05,430 --> 00:09:08,490 If you use -b, it's going to print out the bad blocks 218 00:09:08,490 --> 00:09:09,930 in that file system. 219 00:09:09,930 --> 00:09:13,290 If you use -f, it's going to be used to force the utility 220 00:09:13,290 --> 00:09:15,120 to display the file system status 221 00:09:15,120 --> 00:09:18,180 regardless of whether the file system flags are set or not. 222 00:09:18,180 --> 00:09:20,280 And if you use -i, it's going to be used 223 00:09:20,280 --> 00:09:21,870 to display the file system data 224 00:09:21,870 --> 00:09:25,740 from an image file created using the e2image command. 225 00:09:25,740 --> 00:09:28,260 Now just like our EXT file system types, 226 00:09:28,260 --> 00:09:29,760 there's also tools that allow you 227 00:09:29,760 --> 00:09:32,460 to work with XFS file system types. 228 00:09:32,460 --> 00:09:35,996 The XFS_info command is used to display details 229 00:09:35,996 --> 00:09:40,440 about the XFS file system including its block information. 230 00:09:40,440 --> 00:09:42,982 The XFS_admin command is used 231 00:09:42,982 --> 00:09:46,170 to change the parameters of an XFS file system 232 00:09:46,170 --> 00:09:48,960 including its label and its UUID. 233 00:09:48,960 --> 00:09:51,600 If you use XFS_metadump, 234 00:09:51,600 --> 00:09:54,090 it's going to be used to copy the superblock metadata 235 00:09:54,090 --> 00:09:57,300 of the XFS file system and put that in a file. 236 00:09:57,300 --> 00:10:01,110 If you use XFS_growfs, it's going to be used 237 00:10:01,110 --> 00:10:05,160 to expand the XFS file system to fill the drive size. 238 00:10:05,160 --> 00:10:09,420 If you use XFS_copy, it's going to be used to copy the contents 239 00:10:09,420 --> 00:10:12,750 of the XFS file system to another location. 240 00:10:12,750 --> 00:10:15,284 If you use XFS_repair it's going to be used to repair 241 00:10:15,284 --> 00:10:19,380 and recover a corrupt XFS file system. 242 00:10:19,380 --> 00:10:23,220 And finally, the XFS_db is going to be used 243 00:10:23,220 --> 00:10:26,100 to debug an XFS file system. 244 00:10:26,100 --> 00:10:29,850 Another you should be aware of is the lsscsi command, 245 00:10:29,850 --> 00:10:32,310 also known as the LS SCSI command. 246 00:10:32,310 --> 00:10:34,020 This command is used to list information 247 00:10:34,020 --> 00:10:37,080 about SCSI devices that are connected to a Linux system. 248 00:10:37,080 --> 00:10:38,970 The most common type of SCSI device used 249 00:10:38,970 --> 00:10:40,980 in Linux systems these days is storage 250 00:10:40,980 --> 00:10:42,540 and external hard disk drives, 251 00:10:42,540 --> 00:10:44,580 which is why I'm bringing it up here. 252 00:10:44,580 --> 00:10:48,540 If you simply enter lsscsi at the command line interface 253 00:10:48,540 --> 00:10:51,180 and hit Enter, it's can respond with one line 254 00:10:51,180 --> 00:10:53,880 for each SCSI device attached to your system. 255 00:10:53,880 --> 00:10:55,440 For example, it can tell you 256 00:10:55,440 --> 00:10:59,400 that there is a SCSI hard drive connected at 0080, 257 00:10:59,400 --> 00:11:02,160 and it's mounted at /dev/SDA, 258 00:11:02,160 --> 00:11:05,640 and that drive is manufactured by Fujitsu in this example. 259 00:11:05,640 --> 00:11:08,040 If you want to display the size of the disk as well, 260 00:11:08,040 --> 00:11:13,040 you can do that by using the -s option with lsscsi as well. 261 00:11:13,800 --> 00:11:15,510 Most of us, though, aren't really going to be using 262 00:11:15,510 --> 00:11:17,752 a lot of SCSI devices, because they're fairly old 263 00:11:17,752 --> 00:11:19,590 and antiquated by now. 264 00:11:19,590 --> 00:11:21,960 Instead, though, you may come across fiber channel 265 00:11:21,960 --> 00:11:23,760 connected devices instead. 266 00:11:23,760 --> 00:11:26,490 To interact with these devices and display their statistics, 267 00:11:26,490 --> 00:11:29,610 you can use the fcstat command. 268 00:11:29,610 --> 00:11:32,550 By entering fcstat at the command line interface, 269 00:11:32,550 --> 00:11:34,500 you're going to be able to display general statistics 270 00:11:34,500 --> 00:11:36,120 about fiber channel devices 271 00:11:36,120 --> 00:11:37,620 that are connected to your system, 272 00:11:37,620 --> 00:11:39,450 and this usually represents high speed 273 00:11:39,450 --> 00:11:42,960 and large capacity external storage area network arrays. 274 00:11:42,960 --> 00:11:44,790 If you want more detailed statistics, 275 00:11:44,790 --> 00:11:49,790 you can also enter fcstat-e at your command line interface, 276 00:11:49,980 --> 00:11:52,290 and this way you'll display all the statistics 277 00:11:52,290 --> 00:11:55,530 including device specific statistics, link statistics, 278 00:11:55,530 --> 00:11:58,350 and fiber channel for statistic types. 279 00:11:58,350 --> 00:12:00,540 As I said before, you don't have to memorize 280 00:12:00,540 --> 00:12:02,400 every single one of these commands, 281 00:12:02,400 --> 00:12:04,200 but I just wanted to introduce you to them, 282 00:12:04,200 --> 00:12:06,540 because you may come across them in the real world 283 00:12:06,540 --> 00:12:08,013 in working on Linux systems.