1 00:00:00,520 --> 00:00:03,710 In the last lesson we mentioned cold sites and warm sites, 2 00:00:03,710 --> 00:00:05,310 and for these to work you have to be able 3 00:00:05,310 --> 00:00:07,010 to bring your data and get 'em over 4 00:00:07,010 --> 00:00:09,050 to those new networks that you install there. 5 00:00:09,050 --> 00:00:10,730 Well, to do that you have to have 6 00:00:10,730 --> 00:00:12,680 a good backup to begin with. 7 00:00:12,680 --> 00:00:15,540 Data backups can be conducted using full backups, 8 00:00:15,540 --> 00:00:18,150 incremental backups, or differential backups. 9 00:00:18,150 --> 00:00:19,890 Now, when I discuss each of these types 10 00:00:19,890 --> 00:00:21,740 I'm going to use the word drive to describe 11 00:00:21,740 --> 00:00:23,760 the way data is being backed up. 12 00:00:23,760 --> 00:00:25,400 This can be the entire hard disk, 13 00:00:25,400 --> 00:00:28,170 but it can also be just a file or a folder on that disk 14 00:00:28,170 --> 00:00:30,730 depending on how you scope your backup configurations. 15 00:00:30,730 --> 00:00:32,650 But for the purposes of my explanations 16 00:00:32,650 --> 00:00:34,960 and these definitions, I'm just going to say drive 17 00:00:34,960 --> 00:00:37,370 throughout the rest of the lesson to keep it easy. 18 00:00:37,370 --> 00:00:40,310 Now, the first kind we have is known as a full backup. 19 00:00:40,310 --> 00:00:42,660 When you do a full backup, all of the contents 20 00:00:42,660 --> 00:00:45,960 of your drive are backed up, that's every single file. 21 00:00:45,960 --> 00:00:47,720 Now, when we go to an incremental backup, 22 00:00:47,720 --> 00:00:49,780 which is our second type, this is going to backup 23 00:00:49,780 --> 00:00:51,260 only the contents of the drive 24 00:00:51,260 --> 00:00:53,570 that have changed since the last full backup, 25 00:00:53,570 --> 00:00:56,020 or since your last incremental backup. 26 00:00:56,020 --> 00:00:58,060 Now, the third category we have is known 27 00:00:58,060 --> 00:00:59,670 as a differential backup. 28 00:00:59,670 --> 00:01:02,100 Differential backups will only backup the contents 29 00:01:02,100 --> 00:01:05,260 of the drive that have changed since the last full backup. 30 00:01:05,260 --> 00:01:07,700 So, let's say that every Sunday at 9:00 p.m. 31 00:01:07,700 --> 00:01:10,270 I run a full weekly backup of the drive, 32 00:01:10,270 --> 00:01:12,880 then the rest of the week I use a differential backup 33 00:01:12,880 --> 00:01:14,660 to create backups of any files or folders 34 00:01:14,660 --> 00:01:18,050 that have changed since Sunday when I did that full backup. 35 00:01:18,050 --> 00:01:19,510 This is good because if I have a drive 36 00:01:19,510 --> 00:01:22,130 fail on Wednesday, I can restore from the full backup 37 00:01:22,130 --> 00:01:24,420 we made on Sunday and then the differential backup 38 00:01:24,420 --> 00:01:27,000 that I made on Tuesday, and all the file changes 39 00:01:27,000 --> 00:01:28,610 that happened on Monday and Tuesday 40 00:01:28,610 --> 00:01:31,970 would also be included in that Tuesday differential backup. 41 00:01:31,970 --> 00:01:34,110 Now, there is one problem with full backups, 42 00:01:34,110 --> 00:01:35,900 they take a lot of time. 43 00:01:35,900 --> 00:01:38,170 Differential backups take up less time, 44 00:01:38,170 --> 00:01:39,560 but they can still take a while 45 00:01:39,560 --> 00:01:41,100 if you have a lot of changes, 46 00:01:41,100 --> 00:01:43,160 and so many organizations instead, 47 00:01:43,160 --> 00:01:45,820 use what's known as an incremental backup. 48 00:01:45,820 --> 00:01:48,610 Now, this only creates a backup of everything that's changed 49 00:01:48,610 --> 00:01:50,240 since the last full backup, 50 00:01:50,240 --> 00:01:52,630 or since the last incremental backup. 51 00:01:52,630 --> 00:01:54,140 So let's go back to our example 52 00:01:54,140 --> 00:01:56,130 and configure our backups for our server. 53 00:01:56,130 --> 00:01:57,840 Let's say we decide to do a full backup 54 00:01:57,840 --> 00:01:59,740 every Sunday just like before, 55 00:01:59,740 --> 00:02:01,850 but instead of using a differential backup 56 00:02:01,850 --> 00:02:04,320 we're going to use an incremental backup each night. 57 00:02:04,320 --> 00:02:05,900 This is going to save us some time. 58 00:02:05,900 --> 00:02:07,710 So, Monday we do an incremental, 59 00:02:07,710 --> 00:02:08,980 Tuesday we do an incremental, 60 00:02:08,980 --> 00:02:10,260 Wednesday I do an incremental, 61 00:02:10,260 --> 00:02:13,640 Thursday I do an incremental, and Friday my drive fails. 62 00:02:13,640 --> 00:02:16,760 Which backups do I need to use to restore all my data? 63 00:02:16,760 --> 00:02:19,280 Well, instead of needing Sunday, the full backup, 64 00:02:19,280 --> 00:02:22,270 and Thursday night, if we'd done a differential backup, 65 00:02:22,270 --> 00:02:23,990 we're now going to have to go and get 66 00:02:23,990 --> 00:02:27,090 every single one from Sunday, the full backup, 67 00:02:27,090 --> 00:02:28,600 and then Monday's incremental, 68 00:02:28,600 --> 00:02:30,870 Tuesday's incremental, Wednesday's incremental, 69 00:02:30,870 --> 00:02:32,430 and finally, Thursday's incremental, 70 00:02:32,430 --> 00:02:34,530 and we'll have to restore them in that order. 71 00:02:34,530 --> 00:02:36,260 Now you can see the tough choice we have 72 00:02:36,260 --> 00:02:38,980 between using incrementals and differentials, 73 00:02:38,980 --> 00:02:41,750 because incrementals take a lot less time to backup, 74 00:02:41,750 --> 00:02:44,460 but the differentials make it a lot quicker 75 00:02:44,460 --> 00:02:45,700 when we need to restore, 76 00:02:45,700 --> 00:02:47,750 and so this going to be a choice you have to make. 77 00:02:47,750 --> 00:02:50,540 Do you want quick backups and lengthy restores, 78 00:02:50,540 --> 00:02:54,502 or do you want long backups and quick restores? 79 00:02:54,502 --> 00:02:56,969 (electronic beats)