1
00:00:08,130 --> 00:00:12,000
- So, let's start with f disk on dev sdb.

2
00:00:12,000 --> 00:00:13,290
I think we still have some place

3
00:00:13,290 --> 00:00:15,900
to create logical partitions.

4
00:00:15,900 --> 00:00:17,178
I'm using p,

5
00:00:17,178 --> 00:00:20,210
and I'm checking that we have sdb 4,

6
00:00:21,071 --> 00:00:24,150
sdb 4 goes all the way to the end 2 0 9,

7
00:00:24,150 --> 00:00:28,260
and we have available space
after the end of sdb 5,

8
00:00:28,260 --> 00:00:31,110
and also before sdb 5

9
00:00:31,110 --> 00:00:35,340
because we removed one of
these partitions before.

10
00:00:35,340 --> 00:00:36,173
You know what?

11
00:00:36,173 --> 00:00:38,100
Let's do something funny.

12
00:00:38,100 --> 00:00:39,870
Look carefully, and try to understand.

13
00:00:39,870 --> 00:00:41,970
I'm using N for new.

14
00:00:41,970 --> 00:00:44,160
And it creates partition number 6,

15
00:00:44,160 --> 00:00:44,993
that's okay.

16
00:00:44,993 --> 00:00:48,447
And it wants to create
it at starting 0.8392704,

17
00:00:50,040 --> 00:00:53,730
which is actually before sdb 5.

18
00:00:53,730 --> 00:00:55,200
I'm going to accept that,

19
00:00:55,200 --> 00:00:58,650
and I'm going to use the end 104889855,

20
00:01:01,050 --> 00:01:04,020
which is still before sdb 5.

21
00:01:04,020 --> 00:01:06,750
Now the funny thing is,
that it's telling me,

22
00:01:06,750 --> 00:01:10,650
partition 6 contains an ext4 signature.

23
00:01:10,650 --> 00:01:12,360
Do you want to remove this signature?

24
00:01:12,360 --> 00:01:13,500
I don't.

25
00:01:13,500 --> 00:01:14,500
What is it telling here?

26
00:01:14,500 --> 00:01:18,090
It is telling that it has
found an ext4 file system,

27
00:01:18,090 --> 00:01:19,980
and here it's asking do
you want to remove it?

28
00:01:19,980 --> 00:01:20,973
No, I don't.

29
00:01:21,926 --> 00:01:24,240
I want to show you that

30
00:01:24,240 --> 00:01:27,480
by deleting a partition, you
don't really delete anything,

31
00:01:27,480 --> 00:01:31,650
and if you just deleted the
partition, it's easy to recover.

32
00:01:31,650 --> 00:01:35,790
So now I'm using p and we can see sdb 6.

33
00:01:35,790 --> 00:01:37,620
And the partitions are not in this order.

34
00:01:37,620 --> 00:01:39,660
I don't care about that too much.

35
00:01:39,660 --> 00:01:44,040
I'm going to use this
partition using the UUID.

36
00:01:46,980 --> 00:01:51,780
So I'm going to write this, and blkid,

37
00:01:51,780 --> 00:01:56,613
and blkid on sdb 6 is
showing me this UUID.

38
00:01:59,340 --> 00:02:01,740
I'm copying the UUID,

39
00:02:01,740 --> 00:02:04,233
and I'm getting into etc fstab.

40
00:02:05,070 --> 00:02:08,520
And in etc fstab, I'm adding a new line,

41
00:02:08,520 --> 00:02:12,720
and I'm telling it to mount
this on lesson 12 lab.

42
00:02:12,720 --> 00:02:15,657
And the file system type is ext4,

43
00:02:15,657 --> 00:02:18,273
and the mount options are defaults,

44
00:02:20,100 --> 00:02:21,633
and zero and zero.

45
00:02:23,640 --> 00:02:28,473
And now, I create my
lesson 12 lab directory.

46
00:02:29,400 --> 00:02:31,920
I do my mount minus a,

47
00:02:31,920 --> 00:02:33,840
and oh boy, that's disappointing.

48
00:02:33,840 --> 00:02:36,930
Special device UUID doesn't exist.

49
00:02:36,930 --> 00:02:38,970
How is that possible?

50
00:02:38,970 --> 00:02:40,293
Did I make a typo?

51
00:02:41,430 --> 00:02:42,750
Well you know what?

52
00:02:42,750 --> 00:02:45,660
In partitioning, rebooting
is always a good idea.

53
00:02:45,660 --> 00:02:47,943
Let's reboot, and let's
see how it works out.

54
00:02:49,844 --> 00:02:52,715
Alright, so something
obviously didn't go well,

55
00:02:52,715 --> 00:02:54,093
let's troubleshoot.

56
00:02:56,310 --> 00:03:00,480
So, we can see that time
out waiting for device,

57
00:03:00,480 --> 00:03:02,340
and then we have the UUID.

58
00:03:02,340 --> 00:03:04,230
You can still see it on top of the screen.

59
00:03:04,230 --> 00:03:07,770
It's a UUID ending fb73.

60
00:03:07,770 --> 00:03:12,753
So, I would say blkid
to see if we have fb73.

61
00:03:14,310 --> 00:03:18,690
So fb73 and I'm looking at sdb 5,

62
00:03:18,690 --> 00:03:21,570
and sdb 5 does not have it,

63
00:03:21,570 --> 00:03:25,650
and sdb 6 does have this fb73.

64
00:03:25,650 --> 00:03:27,480
Hmm, that's interesting.

65
00:03:27,480 --> 00:03:31,200
So, the big question is,
what is going on here?

66
00:03:31,200 --> 00:03:32,970
Well, in order to troubleshoot,

67
00:03:32,970 --> 00:03:36,690
the troubleshooting is
definitely related to the UUID.

68
00:03:36,690 --> 00:03:40,380
I would like to mount this, by UUID

69
00:03:40,380 --> 00:03:41,550
and see if that works.

70
00:03:41,550 --> 00:03:44,130
And if I can mount it manually by UUID,

71
00:03:44,130 --> 00:03:45,963
we can put it in etc fstab.

72
00:03:46,920 --> 00:03:50,130
In order to mount it by
UUID from the command line,

73
00:03:50,130 --> 00:03:53,700
that's a little bit challenging,
but it should be doable.

74
00:03:53,700 --> 00:03:55,073
Look, if you use blkid,

75
00:03:56,130 --> 00:03:59,160
first I need to isolate the UUID, right?

76
00:03:59,160 --> 00:04:03,210
So, if i grab sdb 6,

77
00:04:03,210 --> 00:04:05,073
we can do that in a more elegant way,

78
00:04:06,002 --> 00:04:08,310
but this is okay with me.

79
00:04:08,310 --> 00:04:10,439
Awk, print,

80
00:04:10,439 --> 00:04:12,363
dollar, 2,

81
00:04:13,320 --> 00:04:14,793
for the second field.

82
00:04:17,100 --> 00:04:19,518
And there we go, we have the UUID.

83
00:04:19,518 --> 00:04:24,511
Hey, that should be possible
to do it this way as well,

84
00:04:24,511 --> 00:04:27,483
for lines containing.

85
00:04:29,730 --> 00:04:30,780
And that's also working.

86
00:04:30,780 --> 00:04:32,070
This is more elegant, isn't it?

87
00:04:32,070 --> 00:04:34,020
Grep and awk in the same command.

88
00:04:34,020 --> 00:04:35,970
Hey, why would you wanna do that

89
00:04:35,970 --> 00:04:38,070
if you can do it in one command?

90
00:04:38,070 --> 00:04:42,000
Good, so now I need to mount this UUID

91
00:04:42,000 --> 00:04:46,590
and obviously I'm not going
to copy that manually.

92
00:04:46,590 --> 00:04:50,749
I am going to use good
old command substitution

93
00:04:50,749 --> 00:04:53,790
which is, dollar, parenthesis,

94
00:04:53,790 --> 00:04:57,210
and we put this entire
command between parenthesis,

95
00:04:57,210 --> 00:04:59,760
because you should be
able to use mount UUID

96
00:04:59,760 --> 00:05:02,760
equals UUID, and slash mnt.

97
00:05:02,760 --> 00:05:06,390
I'm okay putting it in slash
mnt, just to see if it works.

98
00:05:06,390 --> 00:05:07,680
Well, that works.

99
00:05:07,680 --> 00:05:09,660
Well, as this works,

100
00:05:09,660 --> 00:05:13,694
it almost looks as if it
was a copy paste error.

101
00:05:13,694 --> 00:05:14,883
But,

102
00:05:16,800 --> 00:05:18,003
based on this,

103
00:05:19,050 --> 00:05:22,246
I think it's a good idea to

104
00:05:22,246 --> 00:05:27,246
redirect the output of this
fine command into etc fstab.

105
00:05:28,650 --> 00:05:29,640
There we go.

106
00:05:29,640 --> 00:05:30,690
Let's fix.

107
00:05:30,690 --> 00:05:32,373
Etc fstab again.

108
00:05:33,990 --> 00:05:37,180
And there we have the UUID

109
00:05:39,118 --> 00:05:40,201
and the UUID.

110
00:05:41,235 --> 00:05:42,068
(laughing)

111
00:05:42,068 --> 00:05:42,901
Do you see it?

112
00:05:42,901 --> 00:05:43,734
I see it.

113
00:05:43,734 --> 00:05:45,300
You probably see it as well.

114
00:05:45,300 --> 00:05:48,783
Sometimes, it's just a small thing.

115
00:05:49,718 --> 00:05:54,240
Closing quotes for instance,
I think we found it,

116
00:05:54,240 --> 00:05:55,157
so we can remove this one.

117
00:05:55,157 --> 00:05:56,610
But hey,

118
00:05:56,610 --> 00:05:58,500
we didn't lose any time
in the troubleshooting

119
00:05:58,500 --> 00:06:00,540
because it was cool
troubleshooting, wasn't it?

120
00:06:00,540 --> 00:06:03,810
At the same time, lesson
12 lab, do we have that?

121
00:06:03,810 --> 00:06:07,530
Ls and slash is showing lesson 12 lab,

122
00:06:07,530 --> 00:06:09,120
that is doing alright.

123
00:06:09,120 --> 00:06:12,480
And mount minus A, is that working now?

124
00:06:12,480 --> 00:06:13,680
That is working now.

125
00:06:13,680 --> 00:06:15,180
I want to reboot.

126
00:06:15,180 --> 00:06:18,210
I want to see that this is
happening the way it should be

127
00:06:18,210 --> 00:06:22,533
happening, and I'm expecting
it to be alright at this point.

128
00:06:25,320 --> 00:06:26,153
So there we go.

129
00:06:26,153 --> 00:06:28,860
We already have the GNOME
display manager popping up.

130
00:06:28,860 --> 00:06:30,093
So we are good.

131
00:06:33,090 --> 00:06:35,370
There's just one tiny
little thing that I still

132
00:06:35,370 --> 00:06:36,220
need to show you.

133
00:06:38,250 --> 00:06:39,780
Not because we need to,

134
00:06:39,780 --> 00:06:42,243
but because you wanna
learn cool stuff, right?

135
00:06:50,280 --> 00:06:54,150
So back to the command line interface,

136
00:06:54,150 --> 00:06:58,380
and let's do an f disk on dev, sdb,

137
00:06:58,380 --> 00:07:00,603
and p for print.

138
00:07:04,920 --> 00:07:06,150
And guess what?

139
00:07:06,150 --> 00:07:08,220
Do you see what's happening here?

140
00:07:08,220 --> 00:07:12,390
Suddenly, the previously
known as sda has become sdb.

141
00:07:12,390 --> 00:07:14,100
Now, that's a surprise.

142
00:07:14,100 --> 00:07:16,440
Proves the point of device names changing.

143
00:07:16,440 --> 00:07:19,800
So probably, I need to
do an f disk on dev sda,

144
00:07:19,800 --> 00:07:21,810
what happened to my old sdb?

145
00:07:21,810 --> 00:07:25,470
This is my old sdb, and what berks me here

146
00:07:25,470 --> 00:07:28,350
is partition table entries
are not in disk order,

147
00:07:28,350 --> 00:07:30,660
that is what I want to fix.

148
00:07:30,660 --> 00:07:31,863
How do we fix that?

149
00:07:31,863 --> 00:07:34,950
Well, we have x for expert options,

150
00:07:34,950 --> 00:07:38,100
and in the expert options use m for help.

151
00:07:38,100 --> 00:07:42,750
And you can see that there
is f, fix partitions order.

152
00:07:42,750 --> 00:07:44,250
Just have a look at it right now,

153
00:07:44,250 --> 00:07:46,853
we have sda 5 starting at 104,

154
00:07:46,853 --> 00:07:49,380
and sda 6 starting at 83.

155
00:07:49,380 --> 00:07:52,500
I'm using f, and I'm using r to get back

156
00:07:52,500 --> 00:07:54,690
to the main menu, and then I'm using p,

157
00:07:54,690 --> 00:07:57,960
and then we can see the
partition order is fixed.

158
00:07:57,960 --> 00:08:01,290
Doesn't that hurt the way
how we are starting things?

159
00:08:01,290 --> 00:08:02,520
Well, it shouldn't.

160
00:08:02,520 --> 00:08:04,620
We do need to reboot though,

161
00:08:04,620 --> 00:08:07,260
because in etc fstab, at this point

162
00:08:07,260 --> 00:08:10,593
we should have nothing but
device independent naming.

163
00:08:11,790 --> 00:08:13,140
Doesn't that hurt anything?

164
00:08:13,140 --> 00:08:15,720
No, it doesn't, because in etc fstab

165
00:08:15,720 --> 00:08:18,404
we have nothing but persistent
naming at the moment.

166
00:08:18,404 --> 00:08:21,990
UUID, and labels, and
dev mapper, cs something:

167
00:08:21,990 --> 00:08:22,890
That's LVM.

168
00:08:22,890 --> 00:08:25,110
We'll talk about LVM in the next lesson.

169
00:08:25,110 --> 00:08:26,343
For now, we are done.