Concept Of Raid 5 & Raid 6 In Real World



Concept Of Raid 5 & Raid 6 In Real World
Concept Of Raid 5 & Raid 6 In Real World



Raid 5 and raid 6 now previously I did do a video about raid 0 1 5 and 10 a few years ago but I never covered raid 6 but to understand raid 6 you need to understand raid 5 so that's what we're going to talk about now raid stands for redundant array of independent or inexpensive disks in a raid setup the data is copied or spread on multiple disks. So that in the event of a disk technology no data would be lost because that data is spread on other disks so let's talk about raid 5 now in order to use raid 5 you need to have three or more disks raid 5 is a common setup that is used especially in companies and that's because it's fast and it can store a large amount of data now in a raid 5 setup.

Concept Of Raid 5 & Raid 6 In Real World


 That data is not duplicated but it's striped or spread across multiple disks and in addition to the data there is another very important piece of information that is being evenly spread across all the disks and that information is called parity.  parity is used to rebuild the data in the event of a disk failure now in a raid 5 setup if one disk were to fail you would not lose any data because raid 5 is designed to handle a single disk failure so all you would have to do is replace the failed disk with a new one and then raid 5 would use the parity information from the other disks to rebuild the data on the new hard drive however if two discs were to fail at the same time in a raid 5 setup .


 Data would be lost because raid 5 is not designed to handle two disk failures at the same time it can only handle one disk failure at a time so in our example here this setup is using three disks but since it's using raid 5 the equivalent size of two of these disks are actually used to store data and this is because it takes the equivalent of one entire disk to store parity .So if these disks were one terabyte three of them combined would equal three terabytes but only two terabytes would be used for actual storage because one terabyte would be used to store parity and that brings us to raid 6 now in order to use raid 6 you need to have 4 or more disks now raid 6 is just like raid 5 where the data is striped across all the disks and parity is also spread on all the disks but the difference is in raid 6 parity is spread twice on all the disks and the reason for this double parity .

What is Raid 5 ?


 It can handle two disk failures at the same time so inner raid 6 if two disks were to fail at the same time which is pretty rare no data would be lost and all you would have to do is replace the failed disks and then raid 6 would use the double parity from the other disks to rebuild the data on the new drives so an hour example here raid six is using four drives so that would mean that the equivalent of two of these drives would be used for actual data storage and the equivalent of two disks would be used to store the double parity so again if these disks were one terabyte each that would be equal to four terabytes but only two terabytes would be used to store data and the other two terabytes would be used to store the double parity and it's also important to note that the read performance from raid 5 and raid 6 are about the same but as far as writing data this is where raid 6 suffers greatly because since raid 6 has to write two independent parity blocks instead of one the write performance will be a lot slower when compared to raid 5 so that's the difference between raid 5 and raid 6 .


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