title
Introduction to RAID

description
Info Level: Beginner Presenter: Eli the Computer Guy Length of Class: 34 Minutes Tracks Security / Data Integrity Prerequisites None Purpose of Class This class introduces the student to R.A.I.D. technology (Redundant Array of Inexpensive Disks), it's applications and gives advice for using disk redundancy in the real world.

detail
{'title': 'Introduction to RAID', 'heatmap': [{'end': 1799.078, 'start': 1770.2, 'weight': 1}], 'summary': 'Provides an overview of raid technology, discussing its capability to merge multiple physical hard drives into a single logical hard drive, enhancing storage capacity and performance, and addressing associated challenges. it also covers raid 0, 1, and 5, highlighting their functionalities, risks, and benefits, and explains raid storage arrays, raid options 0, 1, 5, 6, and 10, and the comparison of hardware vs. software raid, as well as raid storage limitations and downsides.', 'chapters': [{'end': 57.579, 'segs': [{'end': 57.579, 'src': 'embed', 'start': 9.889, 'weight': 0, 'content': [{'end': 11.769, 'text': "Hi, well I'm Eli the Computer Guy.", 'start': 9.889, 'duration': 1.88}, {'end': 14.33, 'text': "Today we're going to be talking about RAID.", 'start': 12.109, 'duration': 2.221}, {'end': 20.111, 'text': 'What is RAID? RAID stands for Redundant Array of Inexpensive Disks.', 'start': 14.87, 'duration': 5.241}, {'end': 31.013, 'text': 'Basically what RAID allows you to do is to turn multiple physical hard drives into one logical hard drive that the computer sees.', 'start': 20.691, 'duration': 10.322}, {'end': 34.614, 'text': 'So imagine if you have four hard drives in a row.', 'start': 31.533, 'duration': 3.081}, {'end': 39.875, 'text': "And you don't want them to be considered individual hard drives by the computer.", 'start': 35.374, 'duration': 4.501}, {'end': 45.717, 'text': 'You can turn them into a RAID array, and the computer will see them as one hard drive.', 'start': 40.115, 'duration': 5.602}, {'end': 52.558, 'text': "Instead of seeing hard drives C, D, E, F, and G, it'll only see hard drive C.", 'start': 45.757, 'duration': 6.801}, {'end': 57.579, 'text': "There's a lot of cool things that you can do with RAID, but there's also a lot of problems that come with it.", 'start': 52.558, 'duration': 5.021}], 'summary': 'Eli explains raid, turning multiple disks into one logical drive.', 'duration': 47.69, 'max_score': 9.889, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/X1x9EMd5ywY/pics/X1x9EMd5ywY9889.jpg'}], 'start': 9.889, 'title': 'Raid technology', 'summary': 'Provides an overview of raid technology, highlighting its capability to merge multiple physical hard drives into a single logical hard drive, enhancing storage capacity and performance for data management, and addressing associated challenges.', 'chapters': [{'end': 57.579, 'start': 9.889, 'title': 'Understanding raid technology', 'summary': 'Discusses raid technology, which allows multiple physical hard drives to be combined into one logical hard drive, improving storage capacity and performance for data management, while also presenting potential challenges.', 'duration': 47.69, 'highlights': ['RAID stands for Redundant Array of Inexpensive Disks, enabling the consolidation of multiple physical hard drives into one logical drive recognized by the computer.', 'RAID technology enhances storage capacity and performance, as multiple hard drives can be viewed as a single unit, simplifying data management.', 'Despite its advantages, RAID technology also presents potential challenges and problems that need to be considered when implementing it.']}], 'duration': 47.69, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/X1x9EMd5ywY/pics/X1x9EMd5ywY9889.jpg', 'highlights': ['RAID technology enhances storage capacity and performance by consolidating multiple hard drives into a single logical drive.', 'RAID stands for Redundant Array of Inexpensive Disks, enabling the consolidation of multiple physical hard drives into one logical drive.', 'Despite its advantages, RAID technology presents potential challenges and problems that need to be considered when implementing it.']}, {'end': 470.036, 'segs': [{'end': 139.926, 'src': 'embed', 'start': 96.554, 'weight': 0, 'content': [{'end': 98.695, 'text': 'That is RAID 0, RAID 1, and RAID 5.', 'start': 96.554, 'duration': 2.141}, {'end': 105.185, 'text': 'So 0, 1.', 'start': 98.695, 'duration': 6.49}, {'end': 109.27, 'text': 'and 5 are the standard forms of RAID that are used.', 'start': 105.186, 'duration': 4.084}, {'end': 114.816, 'text': 'RAID 0 is called RAID striping or disk striping.', 'start': 109.751, 'duration': 5.065}, {'end': 129.822, 'text': 'What disk striping does is it allows you to combine multiple hard drives of the same size into one really, really, really big disk.', 'start': 118.877, 'duration': 10.945}, {'end': 139.926, 'text': 'So for disk striping, you can have anywhere between two to 32 hard drives all in a disk striping array.', 'start': 130.262, 'duration': 9.664}], 'summary': 'Raid 0, raid 1, and raid 5 are standard forms of raid, allowing combining multiple hard drives into one big disk, with 2 to 32 hard drives in a raid 0 array.', 'duration': 43.372, 'max_score': 96.554, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/X1x9EMd5ywY/pics/X1x9EMd5ywY96554.jpg'}, {'end': 422.403, 'src': 'embed', 'start': 307.075, 'weight': 1, 'content': [{'end': 315.923, 'text': 'So if that document is striped across all these hard drives and you lose this one little portion in the middle, that means your document is gone,', 'start': 307.075, 'duration': 8.848}, {'end': 316.984, 'text': 'your videos are gone.', 'start': 315.923, 'duration': 1.061}, {'end': 325.211, 'text': 'Any data residing on this RAID array is destroyed because a portion of the bits and bytes have vanished.', 'start': 317.564, 'duration': 7.647}, {'end': 329.392, 'text': "So with RAID 0, It's very fast.", 'start': 325.752, 'duration': 3.64}, {'end': 337.127, 'text': "It allows you to create a larger hard drive out of many smaller hard drives, but there's no redundancy.", 'start': 330.093, 'duration': 7.034}, {'end': 342.696, 'text': 'If a single hard drive fails, then all of your data has disappeared.', 'start': 337.307, 'duration': 5.389}, {'end': 349.76, 'text': 'So you have to make sure, if you are using RAID 0, that you are using some kind of backup system.', 'start': 343.117, 'duration': 6.643}, {'end': 353.923, 'text': 'Because imagine how often hard drives fail.', 'start': 349.921, 'duration': 4.002}, {'end': 366.689, 'text': 'If you put anywhere between two to 32 hard drives all in one computer figure one hard drive in that computer is going to be failing at some point pretty quickly,', 'start': 354.183, 'duration': 12.506}, {'end': 368.07, 'text': 'and then all of your data will be gone.', 'start': 366.689, 'duration': 1.381}, {'end': 374.057, 'text': "So RAID 0, very fast, creates big hard drives, but there's no redundancy whatsoever.", 'start': 368.531, 'duration': 5.526}, {'end': 387.765, 'text': 'Okay, so we just talked about RAID 0.', 'start': 384.983, 'duration': 2.782}, {'end': 389.446, 'text': "Now we're going to be talking about RAID 1.", 'start': 387.765, 'duration': 1.681}, {'end': 393.449, 'text': 'RAID 1 is called Disk Mirroring.', 'start': 389.446, 'duration': 4.003}, {'end': 399.072, 'text': 'What Disk Mirroring does is it creates identical copies of your data.', 'start': 393.929, 'duration': 5.143}, {'end': 404.268, 'text': 'So with Disk Mirroring, you will only have two hard drives.', 'start': 399.953, 'duration': 4.315}, {'end': 413.215, 'text': 'And what happens is when data is written to one hard drive, it is automatically written to the other hard drive.', 'start': 405.349, 'duration': 7.866}, {'end': 418.86, 'text': 'So these disks are complete mirror images of each other.', 'start': 413.576, 'duration': 5.284}, {'end': 422.403, 'text': "Everything that's on this hard drive is on this hard drive.", 'start': 419.681, 'duration': 2.722}], 'summary': 'Raid 0 offers speed but no redundancy; raid 1 provides disk mirroring with two hard drives.', 'duration': 115.328, 'max_score': 307.075, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/X1x9EMd5ywY/pics/X1x9EMd5ywY307075.jpg'}], 'start': 57.899, 'title': 'Raid 0, 1, and 5, and their comparison', 'summary': 'Discusses raid 0, 1, and 5, explaining their functionalities and potential capacity, and it also highlights the risks and benefits of raid 0 and raid 1, emphasizing data redundancy and potential data loss in case of drive failure.', 'chapters': [{'end': 284.962, 'start': 57.899, 'title': 'Understanding raid 0, 1, and 5', 'summary': 'Discusses raid 0, 1, and 5, explaining how raid 0 combines multiple hard drives to create a larger logical drive, with data being written across all drives to enhance read/write speeds, potentially resulting in up to 32 hard drives being combined into a single logical drive.', 'duration': 227.063, 'highlights': ['RAID 0 allows for combining multiple hard drives into one larger logical drive, potentially resulting in up to 32 hard drives being combined into a single logical drive.', 'Data in disk striping is written across all connected hard drives, enhancing read/write speeds and resulting in a faster performance than a single hard drive.', 'The space in disk striping is additive, e.g., four 250GB hard drives combined into one 1TB logical hard drive, showcasing the potential for significant storage expansion.']}, {'end': 470.036, 'start': 285.102, 'title': 'Raid 0 and raid 1 comparison', 'summary': 'Discusses the risks and benefits of raid 0 and raid 1, highlighting how raid 0 offers high speed and capacity but no redundancy, making it prone to complete data loss if a single hard drive fails, while raid 1 provides disk mirroring, ensuring data integrity and the ability to continue operations even if one drive fails.', 'duration': 184.934, 'highlights': ['RAID 1 provides disk mirroring, ensuring data integrity and the ability to continue operations even if one drive fails. RAID 1 creates identical copies of data on two hard drives, allowing the system to remain operational if one drive fails, ensuring data integrity and continuous operations.', 'RAID 0 offers high speed and capacity but no redundancy, making it prone to complete data loss if a single hard drive fails. RAID 0 allows for increased speed and capacity by striping data across multiple drives, but lacks redundancy, making it vulnerable to complete data loss if a single drive fails.']}], 'duration': 412.137, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/X1x9EMd5ywY/pics/X1x9EMd5ywY57899.jpg', 'highlights': ['RAID 0 allows combining up to 32 drives into one logical drive.', 'RAID 0 enhances read/write speeds across all connected drives.', 'RAID 0 showcases significant storage expansion potential.', 'RAID 1 ensures data integrity and continuous operations.', 'RAID 1 creates identical copies of data on two hard drives.', 'RAID 0 offers high speed and capacity but lacks redundancy.']}, {'end': 992.906, 'segs': [{'end': 556.278, 'src': 'embed', 'start': 529.447, 'weight': 1, 'content': [{'end': 535.029, 'text': 'So for disk striping with parity RAID 5, you need to have at least three hard drives.', 'start': 529.447, 'duration': 5.582}, {'end': 542.111, 'text': 'This again can go all the way up to 32 hard drives if you really want to.', 'start': 537.369, 'duration': 4.742}, {'end': 545.033, 'text': 'Now what happens with disk striping?', 'start': 542.892, 'duration': 2.141}, {'end': 548.914, 'text': 'with parity is bit one is written to the first hard drive,', 'start': 545.033, 'duration': 3.881}, {'end': 556.278, 'text': "bit two is written to the second hard drive and then the third hard drive has a duplicate of the first hard drive's data.", 'start': 548.914, 'duration': 7.364}], 'summary': 'For raid 5, use 3-32 hard drives; it stripes data and provides parity for fault tolerance.', 'duration': 26.831, 'max_score': 529.447, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/X1x9EMd5ywY/pics/X1x9EMd5ywY529447.jpg'}, {'end': 634.627, 'src': 'embed', 'start': 607.154, 'weight': 2, 'content': [{'end': 614.337, 'text': 'Hot swappable means you can pull a hard drive out of the computer system while the computer system is running and put a new one in.', 'start': 607.154, 'duration': 7.183}, {'end': 619.62, 'text': 'So if this first hard drive failed, I would pull it out of the system.', 'start': 614.978, 'duration': 4.642}, {'end': 628.279, 'text': 'I would put in a brand new hard drive and then the system would recreate that RAID 5 array.', 'start': 619.62, 'duration': 8.659}, {'end': 634.627, 'text': 'So it would start putting information back on this hard drive and make it part of the array again.', 'start': 628.319, 'duration': 6.308}], 'summary': 'Hot swappable allows replacing hard drives while system is running, ensuring continuous operation.', 'duration': 27.473, 'max_score': 607.154, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/X1x9EMd5ywY/pics/X1x9EMd5ywY607154.jpg'}, {'end': 684.879, 'src': 'embed', 'start': 656.27, 'weight': 0, 'content': [{'end': 664.739, 'text': "So the important part with RAID 5 is it's disk striping, but it allows for one hard drive to fail and you keep all of your data.", 'start': 656.27, 'duration': 8.469}, {'end': 671.856, 'text': 'It improves your performance, so this will be faster than having a single hard drive on the system.', 'start': 667.054, 'duration': 4.802}, {'end': 681.658, 'text': 'It increases the space of that logical hard drive, but not as much as with disk striping RAID 0.', 'start': 673.536, 'duration': 8.122}, {'end': 684.879, 'text': 'Since you have that one redundant disk, you lose that.', 'start': 681.658, 'duration': 3.221}], 'summary': 'Raid 5 provides disk striping, tolerates 1 drive failure, improves performance, and increases logical drive space with some loss.', 'duration': 28.609, 'max_score': 656.27, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/X1x9EMd5ywY/pics/X1x9EMd5ywY656270.jpg'}, {'end': 743.019, 'src': 'embed', 'start': 718.604, 'weight': 5, 'content': [{'end': 727.63, 'text': "So the way you determine the usable space in array 5 array is you add up all the disks that you're putting in the array, whether it's between 3 to 32.", 'start': 718.604, 'duration': 9.026}, {'end': 735.354, 'text': 'So if you had 32 250 gig hard drives in an array to figure out how much space would be on that array,', 'start': 727.63, 'duration': 7.724}, {'end': 743.019, 'text': 'how much usable space you would add up 32 times 250 gigabytes minus 1..', 'start': 735.354, 'duration': 7.665}], 'summary': 'To determine usable space in array 5, add up disks, e.g. 32*250gb - 1', 'duration': 24.415, 'max_score': 718.604, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/X1x9EMd5ywY/pics/X1x9EMd5ywY718604.jpg'}, {'end': 816.816, 'src': 'embed', 'start': 786.881, 'weight': 3, 'content': [{'end': 793.405, 'text': 'RAID 6 is basically like RAID 5, only you get an additional disk for redundancy.', 'start': 786.881, 'duration': 6.524}, {'end': 798.007, 'text': "So it's disk striping with additional redundancy.", 'start': 793.525, 'duration': 4.482}, {'end': 803.63, 'text': 'So you have two hard drives that can fail and your RAID array still exists.', 'start': 798.027, 'duration': 5.603}, {'end': 807.912, 'text': 'Or if you get really complicated, you go all the way up to RAID 10.', 'start': 804.35, 'duration': 3.562}, {'end': 808.712, 'text': 'RAID 10 is mirrors.', 'start': 807.912, 'duration': 0.8}, {'end': 814.775, 'text': 'of two RAID 5 arrays.', 'start': 812.254, 'duration': 2.521}, {'end': 816.816, 'text': 'So this is how complicated it can get.', 'start': 815.136, 'duration': 1.68}], 'summary': 'Raid 6 provides additional redundancy with two disk failure tolerance, while raid 10 involves mirroring of two raid 5 arrays.', 'duration': 29.935, 'max_score': 786.881, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/X1x9EMd5ywY/pics/X1x9EMd5ywY786881.jpg'}, {'end': 930.086, 'src': 'embed', 'start': 901.084, 'weight': 7, 'content': [{'end': 904.547, 'text': 'or a piece of software to create the RAID array.', 'start': 901.084, 'duration': 3.463}, {'end': 911.872, 'text': 'Now, what a hard drive controller is, is it is a card like you would put in any normal computer or server.', 'start': 905.247, 'duration': 6.625}, {'end': 914.954, 'text': "Nowadays, they're normally PCI Express cards.", 'start': 912.232, 'duration': 2.722}, {'end': 919.438, 'text': "Sometimes you can't find PCI cards out there, but they're normally PCI Express.", 'start': 915.395, 'duration': 4.043}, {'end': 930.086, 'text': 'Now what happens is that card goes into your computer and then all the hard drives that you want hooked into the array are then connected to that controller.', 'start': 920.118, 'duration': 9.968}], 'summary': 'A hard drive controller is a pci express card that connects hard drives to create a raid array.', 'duration': 29.002, 'max_score': 901.084, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/X1x9EMd5ywY/pics/X1x9EMd5ywY901084.jpg'}], 'start': 470.557, 'title': 'Raid storage arrays', 'summary': 'Covers raid 5 storage, which allows for one hard drive failure, improves performance, and provides increased storage space. it also explains raid arrays, usable space, raid options 0, 1, 5, 6, and 10, and the process of creating a raid array using controllers or software.', 'chapters': [{'end': 684.879, 'start': 470.557, 'title': 'Understanding raid 5 storage', 'summary': 'Explains raid 5, a disk striping with parity technique, which allows for one hard drive to fail while keeping all the data intact, improves performance, and provides increased storage space with the tradeoff of losing one redundant disk.', 'duration': 214.322, 'highlights': ['RAID 5 allows for one hard drive to fail and still keep all of the data, ensuring data integrity and protection.', 'It improves performance compared to a single hard drive system, providing faster access to data.', 'Disk striping with parity RAID 5 increases the space of the logical hard drive but not as much as disk striping RAID 0, due to the presence of one redundant disk.', "Hot swappable hard drives in RAID 5 enable the replacement of failed drives without disrupting the system's operation, ensuring continuous data availability.", 'RAID 5 requires at least three hard drives and can scale up to 32 hard drives for implementation.']}, {'end': 992.906, 'start': 685.579, 'title': 'Understanding raid arrays', 'summary': 'Explains raid arrays, including the concept of usable space, raid options such as 0, 1, 5, 6, and 10, and the process of creating a raid array using hard drive controllers or software.', 'duration': 307.327, 'highlights': ['RAID 10 involves mirroring two RAID 5 arrays, providing significant redundancy as four out of six hard drives would have to fail before the system shuts down. RAID 10 provides high redundancy as four out of six hard drives would have to fail before the system shuts down.', 'The usable space in a RAID 5 array is determined by adding up all the disks and subtracting one for redundancy, resulting in a single hard drive failure tolerance in the array. The usable space in a RAID 5 array is determined by adding up all the disks and subtracting one for redundancy, providing single hard drive failure tolerance in the array.', 'A hard drive controller is used to configure RAID arrays and allows the user to set up the connected hard drives into different RAID configurations like RAID 5 or mirroring. A hard drive controller is used to configure RAID arrays and allows the user to set up the connected hard drives into different RAID configurations like RAID 5 or mirroring.']}], 'duration': 522.349, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/X1x9EMd5ywY/pics/X1x9EMd5ywY470557.jpg', 'highlights': ['RAID 5 allows for one hard drive to fail and still keep all of the data, ensuring data integrity and protection.', 'RAID 5 requires at least three hard drives and can scale up to 32 hard drives for implementation.', "Hot swappable hard drives in RAID 5 enable the replacement of failed drives without disrupting the system's operation, ensuring continuous data availability.", 'RAID 10 involves mirroring two RAID 5 arrays, providing significant redundancy as four out of six hard drives would have to fail before the system shuts down.', 'It improves performance compared to a single hard drive system, providing faster access to data.', 'The usable space in a RAID 5 array is determined by adding up all the disks and subtracting one for redundancy, providing single hard drive failure tolerance in the array.', 'Disk striping with parity RAID 5 increases the space of the logical hard drive but not as much as disk striping RAID 0, due to the presence of one redundant disk.', 'A hard drive controller is used to configure RAID arrays and allows the user to set up the connected hard drives into different RAID configurations like RAID 5 or mirroring.']}, {'end': 1215.489, 'segs': [{'end': 1047.858, 'src': 'embed', 'start': 1020.889, 'weight': 0, 'content': [{'end': 1024.45, 'text': 'you can pull it out and replace it and the computer can keep running.', 'start': 1020.889, 'duration': 3.561}, {'end': 1031.973, 'text': 'So, even if the RAID that has your operating system on it, if one of the hard drives fails,', 'start': 1024.609, 'duration': 7.364}, {'end': 1035.753, 'text': "you can replace it and the server stays up and running and it's fine.", 'start': 1031.973, 'duration': 3.78}, {'end': 1036.674, 'text': 'There are no problems.', 'start': 1035.794, 'duration': 0.88}, {'end': 1043.896, 'text': 'Hardware RAID is generally very fast and can really give your computer a performance boost.', 'start': 1037.714, 'duration': 6.182}, {'end': 1047.858, 'text': 'Now on the other side is software RAID.', 'start': 1044.938, 'duration': 2.92}], 'summary': 'Hardware raid provides fast and reliable performance, allowing for easy drive replacement without server downtime.', 'duration': 26.969, 'max_score': 1020.889, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/X1x9EMd5ywY/pics/X1x9EMd5ywY1020889.jpg'}, {'end': 1116.886, 'src': 'embed', 'start': 1095.48, 'weight': 2, 'content': [{'end': 1106.143, 'text': "So what's nice with this is if any one of those hard drives that stores data fails, you can pull one out, put a new one in, and rebuild that array.", 'start': 1095.48, 'duration': 10.663}, {'end': 1107.543, 'text': 'All of your data is safe.', 'start': 1106.323, 'duration': 1.22}, {'end': 1109.064, 'text': "You don't have to shut down the server.", 'start': 1107.583, 'duration': 1.481}, {'end': 1110.524, 'text': "Here's the problem.", 'start': 1109.764, 'duration': 0.76}, {'end': 1116.886, 'text': 'If the hard drive containing your operating system dies, then the entire computer shuts down and goes away.', 'start': 1111.184, 'duration': 5.702}], 'summary': 'Raid system ensures data safety with seamless drive replacement.', 'duration': 21.406, 'max_score': 1095.48, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/X1x9EMd5ywY/pics/X1x9EMd5ywY1095480.jpg'}, {'end': 1191.775, 'src': 'embed', 'start': 1140.01, 'weight': 3, 'content': [{'end': 1148.372, 'text': 'Also, depending on how fast your computer is, the software, the operating system is now responsible for that rate.', 'start': 1140.01, 'duration': 8.362}, {'end': 1155.253, 'text': "So if you don't have a lot of RAM or if you don't have a lot of processing power, you can dramatically slow down your computer,", 'start': 1149.072, 'duration': 6.181}, {'end': 1163.135, 'text': 'because your operating system is now using RAM and CPU cycles in order to perform that rate.', 'start': 1155.253, 'duration': 7.882}, {'end': 1167.283, 'text': "So that's one of the downsides with software RAID.", 'start': 1164.002, 'duration': 3.281}, {'end': 1173.666, 'text': 'So hardware RAID combines the hard drives logically at the hardware level.', 'start': 1167.584, 'duration': 6.082}, {'end': 1175.987, 'text': 'You can install an operating system on it.', 'start': 1173.886, 'duration': 2.101}, {'end': 1180.489, 'text': "It's very fast, but it requires more money, basically.", 'start': 1176.387, 'duration': 4.102}, {'end': 1183.15, 'text': 'I have one hardware RAID.', 'start': 1181.65, 'duration': 1.5}, {'end': 1186.872, 'text': 'Again, my cost for it was about $900 for the card.', 'start': 1183.851, 'duration': 3.021}, {'end': 1191.775, 'text': "Whereas software RAID, You don't generally pay a dime more for it.", 'start': 1187.312, 'duration': 4.463}], 'summary': 'Software raid uses ram and cpu, while hardware raid is faster but more expensive.', 'duration': 51.765, 'max_score': 1140.01, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/X1x9EMd5ywY/pics/X1x9EMd5ywY1140010.jpg'}], 'start': 993.976, 'title': 'Raid: hardware vs software', 'summary': 'Compares hardware raid and software raid, highlighting benefits such as fast performance and fault tolerance for hardware raid, while also addressing cost differences, redundancy issues, and performance impacts.', 'chapters': [{'end': 1094.84, 'start': 993.976, 'title': 'Hardware vs software raid', 'summary': 'Explains the benefits of hardware raid, highlighting its ability to install an operating system onto the raid array, as well as its fast performance and fault tolerance, while also contrasting it with software raid that is good for storing data and requires an existing operating system to create the raid.', 'duration': 100.864, 'highlights': ["Hardware RAID allows the installation of an operating system onto the RAID array, providing fault tolerance where if one hard drive fails, it can be replaced without affecting the server's operation.", 'Hardware RAID is generally very fast and can provide a performance boost to the computer.', 'Software RAID, built into most operating systems, requires an existing operating system to create the RAID and is suitable for storing data such as company files, offering redundancy options like RAID 0, 1, 5.']}, {'end': 1215.489, 'start': 1095.48, 'title': 'Raid comparison: hardware vs software', 'summary': 'Discusses the advantages and disadvantages of hardware raid and software raid, highlighting the cost differences, redundancy issues, and performance impacts.', 'duration': 120.009, 'highlights': ['Hardware RAID requires a higher initial investment, with an example cost of about $900 for the card, while software RAID is generally free or already a part of the operating system you own.', 'Software RAID lacks redundancy for the operating system, leading to complete shutdown and loss of data if the operating system fails.', "The operating system's performance in software RAID is dependent on the computer's RAM and processing power, potentially causing significant slowdowns if resources are limited."]}], 'duration': 221.513, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/X1x9EMd5ywY/pics/X1x9EMd5ywY993976.jpg', 'highlights': ['Hardware RAID provides fault tolerance, allowing replacement of failed hard drives without affecting server operation.', 'Hardware RAID offers fast performance and a performance boost to the computer.', 'Software RAID lacks redundancy for the operating system, leading to complete shutdown and data loss if the OS fails.', 'Hardware RAID requires a higher initial investment, costing about $900 for the card, while software RAID is generally free.', "Software RAID's performance is dependent on the computer's resources, potentially causing significant slowdowns."]}, {'end': 1486.532, 'segs': [{'end': 1328.06, 'src': 'embed', 'start': 1255.135, 'weight': 2, 'content': [{'end': 1265.337, 'text': 'But what you have to understand is the size that can be used from any one hard drive can only be as large as the smallest hard drive.', 'start': 1255.135, 'duration': 10.202}, {'end': 1274.036, 'text': 'So we have one 750 GB hard drive, we have one 750, we have one 250 gigabyte hard drive and we have one 100 gigabyte hard drive.', 'start': 1266.077, 'duration': 7.959}, {'end': 1295.715, 'text': 'so in this instance, if we had a raid 5 raid array, we could only use 100 gigabytes from both the 250 and the 750 hard drive.', 'start': 1274.036, 'duration': 21.679}, {'end': 1305.979, 'text': 'So although this hard drive has 750 gigabytes on it, you can only use 100 gigabytes of it, same with the 250 gigabytes.', 'start': 1296.035, 'duration': 9.944}, {'end': 1317.792, 'text': 'Because remember, the information gets striped across So the drives have to be the same size that are allocated to the RAID.', 'start': 1306.36, 'duration': 11.432}, {'end': 1328.06, 'text': 'So if you have a one 100 gig hard drive, even if these other hard drives are bigger, you can only allocate 100 gigabytes from each of these drives.', 'start': 1318.473, 'duration': 9.587}], 'summary': 'In a raid 5 array, the usable size is limited by the smallest hard drive, allowing only 100 gigabytes to be used from each drive.', 'duration': 72.925, 'max_score': 1255.135, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/X1x9EMd5ywY/pics/X1x9EMd5ywY1255135.jpg'}, {'end': 1405.259, 'src': 'embed', 'start': 1372.418, 'weight': 0, 'content': [{'end': 1378.725, 'text': 'So now you have 750 gigabytes of total size for a RAID 5 array, and you actually have 500 gigabytes of storage space.', 'start': 1372.418, 'duration': 6.307}, {'end': 1390.233, 'text': "So does that make sense? Let's do one more example.", 'start': 1386.312, 'duration': 3.921}, {'end': 1394.775, 'text': 'People get confused on this all the time.', 'start': 1390.314, 'duration': 4.461}, {'end': 1405.259, 'text': "So, if you have, let's say, a 320 gigabyte hard drive, you have a 250 gigabyte hard drive and you have a 500 gigabyte hard drive.", 'start': 1394.795, 'duration': 10.464}], 'summary': 'Explaining raid 5 array with 750gb total size and 500gb storage space.', 'duration': 32.841, 'max_score': 1372.418, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/X1x9EMd5ywY/pics/X1x9EMd5ywY1372418.jpg'}], 'start': 1227.714, 'title': 'Raid storage limitations', 'summary': "Discusses array volume and size, raid 5 storage calculation, and raid storage limitations, highlighting that raid arrays are limited by the size of the smallest hard drive, with examples demonstrating 100gb allocation per hard drive and limitations to the smallest drive's size, such as using 250gb out of a 750gb drive when combined with smaller drives.", 'chapters': [{'end': 1328.06, 'start': 1227.714, 'title': 'Array volume and size', 'summary': 'Explains that in a raid array, the size of data that can be used from any hard drive is limited to the size of the smallest hard drive, allowing for allocation of only 100 gigabytes from each hard drive.', 'duration': 100.346, 'highlights': ['RAID Arrays Limitation', 'In a RAID array, the size of data that can be used from any hard drive is limited to the size of the smallest hard drive.', 'Allocation Restriction', 'Allocation is restricted to 100 gigabytes from each hard drive in a RAID array, regardless of the actual capacity of the hard drives.']}, {'end': 1434.049, 'start': 1328.66, 'title': 'Raid 5 storage calculation', 'summary': 'Explains raid 5 storage calculation, demonstrating how different hard drive sizes affect total capacity and usable volume, with an example resulting in 750 gigabytes of total size for a raid 5 array and 500 gigabytes of storage space.', 'duration': 105.389, 'highlights': ['The maximum storage space in a RAID 5 array is determined by the size of the smallest hard drive, such as resulting in 750 gigabytes of total size for a RAID 5 array and 500 gigabytes of storage space.', 'Demonstrates how different hard drive sizes affect total capacity and usable volume, with an example resulting in 750 gigabytes of total size for a RAID 5 array and 500 gigabytes of storage space.', 'Provides examples of RAID 5 storage calculations using different hard drive sizes, such as two 500 GB hard drives and one 250 GB hard drive.']}, {'end': 1486.532, 'start': 1434.049, 'title': 'Raid storage limitations', 'summary': "Explains that when setting up a raid, the total space is limited to the size of the smallest drive, allowing for combining different size hard drives, but restricting the total usable space to the smallest drive's size, such as using 250gb out of a 750gb drive when combined with smaller drives.", 'duration': 52.483, 'highlights': ['When setting up a RAID, the total space is limited to the size of the smallest drive, ensuring that the amount of hard drive space used for the RAID matches for every hard drive.', 'Different size hard drives can be combined in a RAID setup, but the total usable space is restricted to the size of the smallest drive, allowing for using only 250GB out of a 750GB drive when combined with smaller drives.', 'The limitation arises from the fact that the amount of hard drive space used for the RAID has to match for every hard drive, preventing the use of varying capacities within the same RAID setup.']}], 'duration': 258.818, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/X1x9EMd5ywY/pics/X1x9EMd5ywY1227714.jpg', 'highlights': ['The maximum storage space in a RAID 5 array is determined by the size of the smallest hard drive, such as resulting in 750 gigabytes of total size for a RAID 5 array and 500 gigabytes of storage space.', 'Provides examples of RAID 5 storage calculations using different hard drive sizes, such as two 500 GB hard drives and one 250 GB hard drive.', 'Different size hard drives can be combined in a RAID setup, but the total usable space is restricted to the size of the smallest drive, allowing for using only 250GB out of a 750GB drive when combined with smaller drives.', 'In a RAID array, the size of data that can be used from any hard drive is limited to the size of the smallest hard drive.', 'When setting up a RAID, the total space is limited to the size of the smallest drive, ensuring that the amount of hard drive space used for the RAID matches for every hard drive.', 'Allocation is restricted to 100 gigabytes from each hard drive in a RAID array, regardless of the actual capacity of the hard drives.']}, {'end': 2141.016, 'segs': [{'end': 1612.315, 'src': 'embed', 'start': 1583.42, 'weight': 2, 'content': [{'end': 1594.188, 'text': 'So the size of a RAID 0 or RAID 1 disk mirroring two 250 gig hard drives, the size of that array would be 500 gigabytes,', 'start': 1583.42, 'duration': 10.768}, {'end': 1596.33, 'text': 'because you have two 250 gigabyte hard drives in that array.', 'start': 1594.188, 'duration': 2.142}, {'end': 1610.914, 'text': "Now since this mirroring, it's this mirroring that means one drive is an exact copy of the other.", 'start': 1604.511, 'duration': 6.403}, {'end': 1612.315, 'text': "There's complete redundancy.", 'start': 1610.934, 'duration': 1.381}], 'summary': 'Raid 1 with two 250gb hard drives creates 500gb array with complete redundancy.', 'duration': 28.895, 'max_score': 1583.42, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/X1x9EMd5ywY/pics/X1x9EMd5ywY1583420.jpg'}, {'end': 1701.432, 'src': 'embed', 'start': 1669.335, 'weight': 1, 'content': [{'end': 1681.782, 'text': 'so if you have four 250 gigabyte hard drives but one is being used for redundancy, the volume of that then is 750 gigabytes.', 'start': 1669.335, 'duration': 12.447}, {'end': 1689.786, 'text': 'so although the size is one terabyte, you only have 750 gigabytes of usable storage space.', 'start': 1681.782, 'duration': 8.004}, {'end': 1701.432, 'text': 'so again, if you had five 100 gigabyte hard drives in a raid 5, then you would have a RAID that is 500 gigabytes in size.', 'start': 1689.786, 'duration': 11.646}], 'summary': 'One terabyte raid with redundancy has 750gb usable space; raid 5 with 5x100gb has 500gb.', 'duration': 32.097, 'max_score': 1669.335, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/X1x9EMd5ywY/pics/X1x9EMd5ywY1669335.jpg'}, {'end': 1799.078, 'src': 'heatmap', 'start': 1745.568, 'weight': 0, 'content': [{'end': 1760.553, 'text': "So again, if you had, let's say, six 250 gigabyte hard drives, The total size would be 1.5 terabytes because you have six 250 gig hard drives.", 'start': 1745.568, 'duration': 14.985}, {'end': 1770.18, 'text': 'But the volume, since two drives are used for redundancy, the volume would only be one terabyte.', 'start': 1761.433, 'duration': 8.747}, {'end': 1775.504, 'text': 'So you lose a whole 500 gigabytes of volume by having that array.', 'start': 1770.2, 'duration': 5.304}, {'end': 1780.949, 'text': 'So just remember size is the entire size of the array.', 'start': 1776.647, 'duration': 4.302}, {'end': 1786.112, 'text': 'It includes all the hard drive space that is allocated for the full array.', 'start': 1781.309, 'duration': 4.803}, {'end': 1791.034, 'text': 'Volume is the usable space within the array.', 'start': 1787.172, 'duration': 3.862}, {'end': 1799.078, 'text': 'So basically take the size of the array minus whatever is used for redundancy and that gets you volume.', 'start': 1791.514, 'duration': 7.564}], 'summary': 'Using six 250gb hard drives yields 1.5tb total size but only 1tb volume due to redundancy, resulting in a 500gb loss.', 'duration': 35.381, 'max_score': 1745.568, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/X1x9EMd5ywY/pics/X1x9EMd5ywY1745568.jpg'}, {'end': 1926.689, 'src': 'embed', 'start': 1846.698, 'weight': 4, 'content': [{'end': 1855.78, 'text': 'Now if your computer crashes for some reason, the one thing that you do not want to do ever, ever, ever, ever, ever is break that RAID array.', 'start': 1846.698, 'duration': 9.082}, {'end': 1859.121, 'text': 'You need to keep that RAID intact.', 'start': 1856.26, 'duration': 2.861}, {'end': 1864.247, 'text': "So if you have hardware RAID, And I've seen this happen.", 'start': 1859.301, 'duration': 4.946}, {'end': 1870.433, 'text': "Don't go into that hardware configuration and then destroy the RAID and try to create another one.", 'start': 1864.327, 'duration': 6.106}, {'end': 1873.797, 'text': 'Because when you do, all of the data gets lost.', 'start': 1870.694, 'duration': 3.103}, {'end': 1884.826, 'text': "Or if the server crashes, don't pull out the hard drives and stick them into some weird little data recovery devices,", 'start': 1874.758, 'duration': 10.068}, {'end': 1886.447, 'text': 'seeing if you can get anything off.', 'start': 1884.826, 'duration': 1.621}, {'end': 1890.849, 'text': "Because in that process, you can damage the data that's on there.", 'start': 1887.027, 'duration': 3.822}, {'end': 1899.755, 'text': 'And if you put them back in, the computer might not be able to see any of that information, even when it is back up and running.', 'start': 1891.53, 'duration': 8.225}, {'end': 1908.18, 'text': 'So the main thing to remember is with RAIDs, if something happens to the computer overall again, the operating system crashes.', 'start': 1900.355, 'duration': 7.825}, {'end': 1911.141, 'text': "Don't play around with those hard drives.", 'start': 1909.02, 'duration': 2.121}, {'end': 1916.264, 'text': "If you don't really understand how RAID works, hire a professional to come in and take a look at it.", 'start': 1911.201, 'duration': 5.063}, {'end': 1922.327, 'text': 'Because if you mess with that RAID, then all of your data can be gone.', 'start': 1916.984, 'duration': 5.343}, {'end': 1926.689, 'text': "So that's a class on RAID.", 'start': 1924.188, 'duration': 2.501}], 'summary': 'Do not tamper with raid arrays, as it can result in complete data loss. consider hiring a professional if you lack understanding.', 'duration': 79.991, 'max_score': 1846.698, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/X1x9EMd5ywY/pics/X1x9EMd5ywY1846698.jpg'}, {'end': 2042.661, 'src': 'embed', 'start': 2019.503, 'weight': 9, 'content': [{'end': 2030.351, 'text': "So, unless you're dealing with a large company, unless you're dealing with data centers, I don't see any reason to use RAID arrays.", 'start': 2019.503, 'duration': 10.848}, {'end': 2039.358, 'text': "I have seen more often than not that the RAID controller itself fails, so it doesn't matter how redundant all your hard drives are.", 'start': 2031.072, 'duration': 8.286}, {'end': 2042.661, 'text': 'If the RAID controller fails, then what are you going to do?', 'start': 2039.879, 'duration': 2.782}], 'summary': 'Raid arrays may not be necessary for small companies or data centers due to frequent raid controller failures.', 'duration': 23.158, 'max_score': 2019.503, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/X1x9EMd5ywY/pics/X1x9EMd5ywY2019503.jpg'}, {'end': 2130.411, 'src': 'embed', 'start': 2080.507, 'weight': 8, 'content': [{'end': 2090.629, 'text': "So as it stands now, since we have two terabyte hard drives on the market, I don't believe RAID is worth it for the most part.", 'start': 2080.507, 'duration': 10.122}, {'end': 2096.551, 'text': "Now again, if you're in a large company and you're dealing with petabytes of information, of course you need a RAID array.", 'start': 2091.23, 'duration': 5.321}, {'end': 2106.157, 'text': 'But if you are a small business or a home user, even a medium-sized business, i do not believe you need rain.', 'start': 2096.951, 'duration': 9.206}, {'end': 2111.8, 'text': 'i believe a good backup system will do a lot better than raid will.', 'start': 2106.157, 'duration': 5.643}, {'end': 2119.444, 'text': 'with the new backup systems that are out there, even if your hard drive fails, you can have everything back up and running within an hour or two.', 'start': 2111.8, 'duration': 7.644}, {'end': 2124.647, 'text': 'and the raid, even though most of the time it is supposed to be hot swappable.', 'start': 2119.444, 'duration': 5.203}, {'end': 2130.411, 'text': 'a lot of times stupid things happen and it can take a lot longer than an hour or two to fix that raid.', 'start': 2124.647, 'duration': 5.764}], 'summary': 'For small and medium businesses, a good backup system is more effective than raid, with new systems enabling quick recovery within hours.', 'duration': 49.904, 'max_score': 2080.507, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/X1x9EMd5ywY/pics/X1x9EMd5ywY2080507.jpg'}], 'start': 1486.552, 'title': 'Understanding raid and its limitations', 'summary': 'Explains array size vs. volume, raid data protection, and downsides of raid, including examples of raid configurations and the impact on storage space. it emphasizes the importance of maintaining raid integrity to avoid data loss, and discusses the diminishing value of raid due to increasing hard drive capacity and the efficiency of modern backup systems.', 'chapters': [{'end': 1823.125, 'start': 1486.552, 'title': 'Understanding array size and volume', 'summary': 'Explains the difference between array size and volume, using examples of various raid configurations to demonstrate the concept, emphasizing the impact on usable storage space and redundancy.', 'duration': 336.573, 'highlights': ['RAID 6 with 6x250GB hard drives has a size of 1.5TB but a volume of 1TB due to 2 drives for redundancy, resulting in a loss of 500GB of volume.', 'RAID 5 with 4x250GB hard drives has a size of 1TB but a volume of 750GB due to 1 drive used for redundancy, affecting the usable storage space.', 'RAID 1 with 2x250GB hard drives has a size of 500GB, but the volume is only 250GB due to mirroring, demonstrating the impact of redundancy on usable capacity.', 'RAID 0 with 4x500GB hard drives results in both size and volume being 2TB, showcasing an exception where size and volume are equal due to all disks being used in the array.']}, {'end': 1963.415, 'start': 1823.946, 'title': 'Raid data protection', 'summary': 'Emphasizes the importance of maintaining raid integrity in the event of server crashes, warning against breaking the raid array as it could result in data loss and advising to seek professional help if unfamiliar with raid operations.', 'duration': 139.469, 'highlights': ['Breaking the RAID array can result in data loss, emphasizing the importance of maintaining RAID integrity (quantifiable data: potential loss of all data).', 'Advising against attempting to recover data by using unfamiliar devices, as it can lead to data damage and potential loss (quantifiable data: risk of damaging data).', 'Emphasizing the need to seek professional help if unfamiliar with RAID operations to avoid risking data loss (quantifiable data: potential loss of all data).', 'Highlighting the significance of RAID as a crucial invention for computer data protection (quantifiable data: historical importance of RAID).']}, {'end': 2141.016, 'start': 1964.055, 'title': 'The downsides of using raid', 'summary': 'Discusses the diminishing value of raid arrays due to the increasing capacity of hard drives, the high likelihood of raid controller failure, and the efficiency of modern backup systems in small to medium-sized businesses and home users compared to raid.', 'duration': 176.961, 'highlights': ['RAID arrays may not be worth it for small to medium-sized businesses and home users due to the availability of two terabyte hard drives and the efficiency of modern backup systems. The chapter highlights that with the availability of two terabyte hard drives and efficient modern backup systems, RAID arrays may not be worth it for small to medium-sized businesses and home users.', 'RAID controller failure is a common occurrence, and obtaining a replacement can be time-consuming, especially for small to medium-sized businesses and home users. The chapter emphasizes the common occurrence of RAID controller failure and the time-consuming process of obtaining a replacement, particularly for small to medium-sized businesses and home users.', 'The chapter advises against using RAID for small to medium-sized businesses and home users, citing the efficiency of modern backup systems in restoring data compared to the potential delays in fixing RAID issues. The chapter advises against using RAID for small to medium-sized businesses and home users, highlighting the efficiency of modern backup systems in restoring data compared to potential delays in fixing RAID issues.']}], 'duration': 654.464, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/X1x9EMd5ywY/pics/X1x9EMd5ywY1486552.jpg', 'highlights': ['RAID 6 with 6x250GB hard drives has a size of 1.5TB but a volume of 1TB due to 2 drives for redundancy, resulting in a loss of 500GB of volume.', 'RAID 5 with 4x250GB hard drives has a size of 1TB but a volume of 750GB due to 1 drive used for redundancy, affecting the usable storage space.', 'RAID 1 with 2x250GB hard drives has a size of 500GB, but the volume is only 250GB due to mirroring, demonstrating the impact of redundancy on usable capacity.', 'RAID 0 with 4x500GB hard drives results in both size and volume being 2TB, showcasing an exception where size and volume are equal due to all disks being used in the array.', 'Breaking the RAID array can result in data loss, emphasizing the importance of maintaining RAID integrity (quantifiable data: potential loss of all data).', 'Advising against attempting to recover data by using unfamiliar devices, as it can lead to data damage and potential loss (quantifiable data: risk of damaging data).', 'Emphasizing the need to seek professional help if unfamiliar with RAID operations to avoid risking data loss (quantifiable data: potential loss of all data).', 'Highlighting the significance of RAID as a crucial invention for computer data protection (quantifiable data: historical importance of RAID).', 'RAID arrays may not be worth it for small to medium-sized businesses and home users due to the availability of two terabyte hard drives and the efficiency of modern backup systems. The chapter highlights that with the availability of two terabyte hard drives and efficient modern backup systems, RAID arrays may not be worth it for small to medium-sized businesses and home users.', 'RAID controller failure is a common occurrence, and obtaining a replacement can be time-consuming, especially for small to medium-sized businesses and home users. The chapter emphasizes the common occurrence of RAID controller failure and the time-consuming process of obtaining a replacement, particularly for small to medium-sized businesses and home users.', 'The chapter advises against using RAID for small to medium-sized businesses and home users, citing the efficiency of modern backup systems in restoring data compared to the potential delays in fixing RAID issues. The chapter advises against using RAID for small to medium-sized businesses and home users, highlighting the efficiency of modern backup systems in restoring data compared to potential delays in fixing RAID issues.']}], 'highlights': ['RAID 0 allows combining up to 32 drives into one logical drive.', 'RAID 5 allows for one hard drive to fail and still keep all of the data, ensuring data integrity and protection.', 'RAID 1 ensures data integrity and continuous operations.', 'RAID 10 involves mirroring two RAID 5 arrays, providing significant redundancy as four out of six hard drives would have to fail before the system shuts down.', 'Hardware RAID provides fault tolerance, allowing replacement of failed hard drives without affecting server operation.', 'RAID technology enhances storage capacity and performance by consolidating multiple hard drives into a single logical drive.', 'RAID stands for Redundant Array of Inexpensive Disks, enabling the consolidation of multiple physical hard drives into one logical drive.', 'RAID 0 enhances read/write speeds across all connected drives.', 'RAID 5 requires at least three hard drives and can scale up to 32 hard drives for implementation.', 'RAID 0 offers high speed and capacity but lacks redundancy.', 'RAID 1 creates identical copies of data on two hard drives.', 'RAID 5 allows for hot swappable hard drives, ensuring continuous data availability.', 'RAID 5 provides single hard drive failure tolerance in the array.', 'Hardware RAID offers fast performance and a performance boost to the computer.', 'RAID 5 with 4x250GB hard drives has a size of 1TB but a volume of 750GB due to 1 drive used for redundancy, affecting the usable storage space.', 'RAID 6 with 6x250GB hard drives has a size of 1.5TB but a volume of 1TB due to 2 drives for redundancy, resulting in a loss of 500GB of volume.']}