1 00:00:00,900 --> 00:00:03,000 In the last lesson, we covered backups 2 00:00:03,000 --> 00:00:05,140 and the most commonly used backup media, 3 00:00:05,140 --> 00:00:06,960 known as the backup tape. 4 00:00:06,960 --> 00:00:09,230 Now, while you don't need to know the specific of tapes 5 00:00:09,230 --> 00:00:12,680 like their sizes and capacities because those vary greatly, 6 00:00:12,680 --> 00:00:14,330 you do need to have a good idea 7 00:00:14,330 --> 00:00:16,110 of the method of rotating tapes, 8 00:00:16,110 --> 00:00:17,620 which means how are we going to determine 9 00:00:17,620 --> 00:00:19,430 how long a tape is going to be kept 10 00:00:19,430 --> 00:00:21,140 and when it can be overwritten? 11 00:00:21,140 --> 00:00:23,050 Now, there are three main rotation schemes 12 00:00:23,050 --> 00:00:24,830 that we're going to cover in Security Plus. 13 00:00:24,830 --> 00:00:26,460 We have the 10 tape rotation, 14 00:00:26,460 --> 00:00:29,890 the grandfather-father-son, and the towers of Hanoi. 15 00:00:29,890 --> 00:00:32,350 Now, the 10 tape rotation is a simple method 16 00:00:32,350 --> 00:00:35,380 that provides easy access to the data that's been backed up. 17 00:00:35,380 --> 00:00:37,990 It could be accomplished during a two-week backup period. 18 00:00:37,990 --> 00:00:39,650 Why is it called a 10 tape rotation 19 00:00:39,650 --> 00:00:41,490 instead of a 14 tape rotation? 20 00:00:41,490 --> 00:00:44,170 Well, because most companies are open Monday through Friday, 21 00:00:44,170 --> 00:00:45,650 so weekends don't count. 22 00:00:45,650 --> 00:00:47,900 If you wanted to do it seven days a week for two weeks, 23 00:00:47,900 --> 00:00:50,580 you could simply call it a 14 tape rotation instead 24 00:00:50,580 --> 00:00:52,070 and use 14 tapes. 25 00:00:52,070 --> 00:00:54,320 Either way, the concept is the same. 26 00:00:54,320 --> 00:00:57,090 Each tape is going to be used once per day for two weeks, 27 00:00:57,090 --> 00:00:59,910 and then, the entire set is reused again. 28 00:00:59,910 --> 00:01:01,350 This means after two weeks, 29 00:01:01,350 --> 00:01:03,470 you don't have anymore backups though. 30 00:01:03,470 --> 00:01:06,890 Now, the second method is known as a grandfather-father-son, 31 00:01:06,890 --> 00:01:10,320 and it's a backup rotation system that's very commonly used. 32 00:01:10,320 --> 00:01:11,990 It's actually one of my favorites. 33 00:01:11,990 --> 00:01:13,490 When attempting to use this design, 34 00:01:13,490 --> 00:01:15,050 there are three sets of backup tapes 35 00:01:15,050 --> 00:01:16,340 that have to be defined. 36 00:01:16,340 --> 00:01:18,960 Usually, we call these the daily, the son; 37 00:01:18,960 --> 00:01:22,330 the weekly, the father; and the monthly, the grandfather. 38 00:01:22,330 --> 00:01:24,800 These tapes are then rotated on a daily basis, 39 00:01:24,800 --> 00:01:25,960 and the last one of the week 40 00:01:25,960 --> 00:01:28,150 will be graduated to father status. 41 00:01:28,150 --> 00:01:29,930 Then, these tapes, the weekly ones, 42 00:01:29,930 --> 00:01:31,720 are then rotated on a weekly basis, 43 00:01:31,720 --> 00:01:34,200 and after four weeks, they become the monthly, 44 00:01:34,200 --> 00:01:36,630 or the grandfather, and that is how we get 45 00:01:36,630 --> 00:01:39,170 our grandfather, fathers, and sons. 46 00:01:39,170 --> 00:01:41,690 Generally, your monthly tapes are kept offsite, 47 00:01:41,690 --> 00:01:43,330 and this will allow you to ensure that they're safe 48 00:01:43,330 --> 00:01:46,010 in case of an emergency at your regular facility or site. 49 00:01:46,010 --> 00:01:48,360 I mean, it would be horrible if your site burned down 50 00:01:48,360 --> 00:01:50,730 and you couldn't do any backups because all your tapes 51 00:01:50,730 --> 00:01:52,120 were in the server room, right? 52 00:01:52,120 --> 00:01:53,500 So you want to make sure you have some good 53 00:01:53,500 --> 00:01:55,340 offsite backups as well. 54 00:01:55,340 --> 00:01:58,430 Now, the third type we have is called the towers of Hanoi, 55 00:01:58,430 --> 00:02:00,950 and this a rotation system that's based on the puzzle 56 00:02:00,950 --> 00:02:02,250 called the towers of Hanoi 57 00:02:02,250 --> 00:02:03,759 that you might've played as a kid. 58 00:02:03,759 --> 00:02:06,240 Much like the grandfather, father, and son, 59 00:02:06,240 --> 00:02:08,707 this system also uses three sets of backups, 60 00:02:08,707 --> 00:02:11,240 but they're rotated a bit differently. 61 00:02:11,240 --> 00:02:14,420 Basically, your first tape is used every second day, 62 00:02:14,420 --> 00:02:16,970 and the second tape is used every fourth day, 63 00:02:16,970 --> 00:02:19,620 and the third tape is used every eighth day, 64 00:02:19,620 --> 00:02:21,340 and so this system helps prevent tapes 65 00:02:21,340 --> 00:02:22,780 from being worn out as quickly 66 00:02:22,780 --> 00:02:24,430 as the 10 tape rotation does, 67 00:02:24,430 --> 00:02:26,930 and it does allow for three different categories of backups 68 00:02:26,930 --> 00:02:29,240 like the grandfather, father, and son method, 69 00:02:29,240 --> 00:02:31,070 but because of this complexity, 70 00:02:31,070 --> 00:02:33,800 it makes it harder to remember what tapes do I use to backup 71 00:02:33,800 --> 00:02:36,110 and in which order, and then when I go to restore, 72 00:02:36,110 --> 00:02:37,820 I have to figure that out as well. 73 00:02:37,820 --> 00:02:40,380 For example, we might use category one in this schedule 74 00:02:40,380 --> 00:02:43,110 as our differential backups and then use category two 75 00:02:43,110 --> 00:02:44,510 as our incremental backups 76 00:02:44,510 --> 00:02:46,800 and category three as our full backups. 77 00:02:46,800 --> 00:02:48,810 You can see how this becomes difficult to keep track of, 78 00:02:48,810 --> 00:02:49,643 right? 79 00:02:49,643 --> 00:02:51,850 Personally, I've always favored the grandfather, 80 00:02:51,850 --> 00:02:53,080 father, and son method, 81 00:02:53,080 --> 00:02:55,140 and that's the one I use in most of my organizations, 82 00:02:55,140 --> 00:02:57,620 but a lot of people like the towers of Hanoi, 83 00:02:57,620 --> 00:02:59,470 and it's one of those things that test writers 84 00:02:59,470 --> 00:03:01,070 really love to see on the exam 85 00:03:01,070 --> 00:03:02,660 because of that distinctive name. 86 00:03:02,660 --> 00:03:05,280 If you see a question about towers of Hanoi on the exam, 87 00:03:05,280 --> 00:03:06,620 just remember, it's referring to a 88 00:03:06,620 --> 00:03:08,670 backup tape rotation strategy. 89 00:03:08,670 --> 00:03:10,880 Now, in addition to our tape backups, 90 00:03:10,880 --> 00:03:13,310 because network storage has become so much cheaper, 91 00:03:13,310 --> 00:03:16,270 and virtual machines are become much, much more common, 92 00:03:16,270 --> 00:03:18,180 there's also an entire system backup 93 00:03:18,180 --> 00:03:20,050 known as a snapshot. 94 00:03:20,050 --> 00:03:22,510 With a snapshot, all of the applications, 95 00:03:22,510 --> 00:03:24,840 the hard drives, and even the operating system 96 00:03:24,840 --> 00:03:27,610 is backed up to create a full backup of the system 97 00:03:27,610 --> 00:03:29,310 as a virtual disc image. 98 00:03:29,310 --> 00:03:30,640 This makes it very quick 99 00:03:30,640 --> 00:03:32,800 to redeploy that system onto a cloud server 100 00:03:32,800 --> 00:03:35,620 or another offsite location, but it does take up 101 00:03:35,620 --> 00:03:37,200 a lot of storage space, 102 00:03:37,200 --> 00:03:39,220 so you need to plan for that extra storage resources 103 00:03:39,220 --> 00:03:41,330 and costs that are involved in using snapshots 104 00:03:41,330 --> 00:03:43,080 instead of regular backups. 105 00:03:43,080 --> 00:03:46,010 Snapshots are also commonly used with virtualized systems, 106 00:03:46,010 --> 00:03:48,120 so if you're running VMware or VirtualBox, 107 00:03:48,120 --> 00:03:49,770 you can take a snapshot of your server 108 00:03:49,770 --> 00:03:53,249 and create that full backup of the entire virtual system. 109 00:03:53,249 --> 00:03:55,716 (electronic whirring)