1 00:00:00,360 --> 00:00:02,370 In this lesson, you're going to learn how 2 00:00:02,370 --> 00:00:04,710 to monitor devices and explore tools 3 00:00:04,710 --> 00:00:07,020 for spotting possible hard drive failures, 4 00:00:07,020 --> 00:00:08,640 displaying hardware information 5 00:00:08,640 --> 00:00:11,730 and checking if the hardware is functioning as expected. 6 00:00:11,730 --> 00:00:15,330 Needless to say, Linux is a very robust operating system, 7 00:00:15,330 --> 00:00:17,610 and it has a large number of excellent utilities 8 00:00:17,610 --> 00:00:20,370 for discovering hardware and monitoring hardware health 9 00:00:20,370 --> 00:00:22,500 that's connected to that computer. 10 00:00:22,500 --> 00:00:25,800 As a Linux administrator, after you set up your devices, 11 00:00:25,800 --> 00:00:28,200 you need to be able to track those devices that are used 12 00:00:28,200 --> 00:00:31,050 on all the computers on the network and maintain a list 13 00:00:31,050 --> 00:00:33,360 of the hardware resources in use. 14 00:00:33,360 --> 00:00:35,550 To do this, one of the most valuable commands 15 00:00:35,550 --> 00:00:37,980 we'll use is lsdev. 16 00:00:37,980 --> 00:00:40,140 lsdev will display information 17 00:00:40,140 --> 00:00:42,210 about your computer's installed hardware 18 00:00:42,210 --> 00:00:44,730 from the interrupts, also the IO ports 19 00:00:44,730 --> 00:00:48,390 and the DMA files inside the /proc directory. 20 00:00:48,390 --> 00:00:50,220 This will give you a quick overview 21 00:00:50,220 --> 00:00:53,280 of which hardware is using which input output addresses 22 00:00:53,280 --> 00:00:57,120 and what IRQs, or interrupts, and DM channels are in use. 23 00:00:57,120 --> 00:00:59,400 This program only shows the kernel's idea 24 00:00:59,400 --> 00:01:01,170 of what hardware is present though, 25 00:01:01,170 --> 00:01:03,780 not what's actually physically available. 26 00:01:03,780 --> 00:01:08,070 The /proc/interrupts file will list each logical CPU core 27 00:01:08,070 --> 00:01:10,230 and its associate interrupt requests. 28 00:01:10,230 --> 00:01:12,930 An IRQ, or interrupt, is simply a signal 29 00:01:12,930 --> 00:01:15,090 that's sent by device to the processor, 30 00:01:15,090 --> 00:01:17,100 so the processor can stop what it's doing 31 00:01:17,100 --> 00:01:20,160 and handle some task that that hardware needs to perform, 32 00:01:20,160 --> 00:01:22,890 like if you pressed a keystroke, or you moved the mouse. 33 00:01:22,890 --> 00:01:24,510 The processor needs to know that, 34 00:01:24,510 --> 00:01:26,250 so it can take action on it. 35 00:01:26,250 --> 00:01:29,310 There are multiple IRQ addresses, or interrupt addresses, 36 00:01:29,310 --> 00:01:31,350 that can signal and be sent along 37 00:01:31,350 --> 00:01:32,880 and for each of those addresses, 38 00:01:32,880 --> 00:01:35,280 the file is going to list how many signals were sent 39 00:01:35,280 --> 00:01:38,550 to each CPU core along with that address. 40 00:01:38,550 --> 00:01:42,840 Another list you need to look at is /proc/ioports. 41 00:01:42,840 --> 00:01:46,020 This is a file that's going to list input and output ports 42 00:01:46,020 --> 00:01:48,810 and the hardware devices that are mapped to those. 43 00:01:48,810 --> 00:01:52,410 On the other hand, we also have /proc/dma. 44 00:01:52,410 --> 00:01:55,950 This is a file that lists all the ISA direct memory 45 00:01:55,950 --> 00:01:59,310 access channels that are going to be used on that system. 46 00:01:59,310 --> 00:02:02,940 ISA DMA is a hardware controller that typically supports 47 00:02:02,940 --> 00:02:06,720 legacy technologies like old-school floppy discs. 48 00:02:06,720 --> 00:02:10,229 Another command we're going to use is lsusb. 49 00:02:10,229 --> 00:02:13,470 The lsusb command is used to display information 50 00:02:13,470 --> 00:02:17,550 about what devices are connected to the system's USB buses. 51 00:02:17,550 --> 00:02:22,350 This command will scan the /dev/bus/usb directory 52 00:02:22,350 --> 00:02:24,150 for all of its information. 53 00:02:24,150 --> 00:02:27,060 By default, the command will print the number of the bus 54 00:02:27,060 --> 00:02:28,770 and the connected device as well 55 00:02:28,770 --> 00:02:31,290 as the ID of the device and the name of the vendor 56 00:02:31,290 --> 00:02:33,600 and product that matches that device. 57 00:02:33,600 --> 00:02:35,940 If you use the -v flag with this command, 58 00:02:35,940 --> 00:02:39,120 you'll see more detailed information about each device. 59 00:02:39,120 --> 00:02:42,570 You can also filter out your results by using -s, 60 00:02:42,570 --> 00:02:45,750 which will show you it by bus, or by using -d, 61 00:02:45,750 --> 00:02:48,360 which will then filter it by the vendor or product. 62 00:02:48,360 --> 00:02:53,310 To run this command, type in lsusb and the options you want. 63 00:02:53,310 --> 00:02:56,550 Another command we have is lspci, 64 00:02:56,550 --> 00:02:58,920 and this one is going to be used to display information 65 00:02:58,920 --> 00:03:00,600 about devices that are connected 66 00:03:00,600 --> 00:03:04,710 through your system's PCI buses or PCI Express buses. 67 00:03:04,710 --> 00:03:07,380 By default, the output of this list will show you 68 00:03:07,380 --> 00:03:09,750 all the logical slot addresses that are typically 69 00:03:09,750 --> 00:03:13,650 in the format of Bus:Device.Function. 70 00:03:13,650 --> 00:03:15,780 It's also going to have the device's class, 71 00:03:15,780 --> 00:03:18,600 such as a network controller, a storage controller, 72 00:03:18,600 --> 00:03:20,820 an input device or a bridge device. 73 00:03:20,820 --> 00:03:23,550 It'll also have the vendor name and the device name. 74 00:03:23,550 --> 00:03:28,530 To run this command, simply type in lspci and the options. 75 00:03:28,530 --> 00:03:30,450 The next command we have is going to allow us 76 00:03:30,450 --> 00:03:32,070 to see what's in the print queue, 77 00:03:32,070 --> 00:03:35,310 and we do this by typing in lpq. 78 00:03:35,310 --> 00:03:38,490 Now, lpq is the list print queue command. 79 00:03:38,490 --> 00:03:40,620 It's going to show the status of your print queue 80 00:03:40,620 --> 00:03:43,620 and by default, it's going to report each print job's rank 81 00:03:43,620 --> 00:03:47,070 in the queue, who owns that job, the job number, 82 00:03:47,070 --> 00:03:50,160 the files in that job and the size of the job. 83 00:03:50,160 --> 00:03:52,830 You can also have the report update every few seconds, 84 00:03:52,830 --> 00:03:56,670 if you want, by specifying this with the +interval option 85 00:03:56,670 --> 00:03:58,740 until that queue becomes empty. 86 00:03:58,740 --> 00:04:01,110 If you don't want to specify the printer to monitor, 87 00:04:01,110 --> 00:04:04,440 the lpq command will monitor your default printer. 88 00:04:04,440 --> 00:04:05,430 To run this command, 89 00:04:05,430 --> 00:04:08,970 simply type in lpq and then the options. 90 00:04:08,970 --> 00:04:10,980 Now, there's some other tools we need to talk about, 91 00:04:10,980 --> 00:04:12,720 and some of these are ones we've already talked 92 00:04:12,720 --> 00:04:14,940 about in the course, but they're also useful 93 00:04:14,940 --> 00:04:17,010 for monitoring hardware devices. 94 00:04:17,010 --> 00:04:20,100 For example, if you want to identify block storage devices 95 00:04:20,100 --> 00:04:21,600 that are connected to your system, 96 00:04:21,600 --> 00:04:26,370 you can use the lsbk command or list block devices. 97 00:04:26,370 --> 00:04:28,680 The output of this command will help you ensure 98 00:04:28,680 --> 00:04:30,540 that you understand what storage devices 99 00:04:30,540 --> 00:04:33,120 are being recognized and used on your system 100 00:04:33,120 --> 00:04:36,180 as well as if they're correctly partitioned and mounted. 101 00:04:36,180 --> 00:04:39,660 Another example of this would be the dmesg command 102 00:04:39,660 --> 00:04:41,490 or D-message command. 103 00:04:41,490 --> 00:04:44,280 If you remember, this is going to print out all the messages 104 00:04:44,280 --> 00:04:46,320 that were sent to the kernel's message buffer 105 00:04:46,320 --> 00:04:48,840 after the system boot, including messages 106 00:04:48,840 --> 00:04:50,700 that were sent by the device drivers. 107 00:04:50,700 --> 00:04:53,340 So it can be very helpful in doing troubleshooting. 108 00:04:53,340 --> 00:04:55,590 If you have a hardware device that encounters errors 109 00:04:55,590 --> 00:04:57,240 in its operation, or they're not able 110 00:04:57,240 --> 00:04:59,670 to load up the expected modules to the kernel, 111 00:04:59,670 --> 00:05:03,120 the output of the D-message might help you figure this out. 112 00:05:03,120 --> 00:05:05,580 Also, you can use this output to monitor 113 00:05:05,580 --> 00:05:07,470 for issues related to device drivers 114 00:05:07,470 --> 00:05:09,770 and the underlying hardware that they control.