Time
10 hours 41 minutes
Difficulty
Beginner
CEU/CPE
12

Video Transcription

00:05
also briefly stepped through. So the common raid levels here. So here we have raised zero,
00:12
which is Ah, block level striping without parody. You're marrying. Which means
00:17
we're gonna make all these hard drives look as one volume.
00:20
They have broken the blocks that ran two separate dis simultaneously on the same sector. No redundancy, but doesn't prove performance.
00:29
Zero arrow checking,
00:33
Um, or just the bigger the volume and the higher the band with. But it's also the greater the risk of data loss
00:41
because you only have to. We have 10 desk, we lose one. We lose them all
00:48
requires at least two to do. Strapping
00:51
raid zero.
00:54
The red one is the other common one often referred to also as mirroring.
00:59
We're the same data is right identically to both dis So here you can see. So
01:04
So we have a piece of dad that's gonna come in and be written to the raid one that's gonna get written both toe justice in this disc and
01:15
and these will be identical Mirrors provides 100%. Redundancy is always with. Only one Dr has failed
01:21
that point. You should probably back up or at another drive and recreate your mirror.
01:29
It's faster. Does have improved reforms for Reed because you have to drive the same information. So if someone comes in looking, if you're pulling a bunch of data about eight to, you want to come in and pull a one wolf. This one's already being frog with a lot of activity. It can come grab it off here so you have a greater source. Could
01:46
the same information at both places. So if one hard drive is busy and go the other hard drive for that same information
01:52
so it's faster on Reid's than in his own rights.
01:56
So So key differences. Everything's kind of based off their own one. So
02:00
zero, which is striping and no redundancy. Fast, right?
02:06
Raid one is mirroring with four redundancy. Fast read.
02:17
All right to, uh, not as common as the red one in, uh, 02 bit level striping with dedicated hamming code parodies. So we have Perry now for error checking.
02:30
Ah, what this means all dis spindle rotations synchronized and data striped such that each sequential bit is on a different desk desk concert theoretical not used today.
02:39
So, uh, you see here So
02:44
all the information spread out between these four disc and this is the parody code checking. The idea is that you could lose a section and be able to recover based off the air code checking here. Um, like I said, it's theoretical
02:59
Raid Ray. Level three is bite level striping with dedicated parody, uh, data stripes or each sequential by is on a different disc
03:07
that helps spread out so far in this fails. You already you start information about the disc on, uh, the other three
03:17
parody is calculated. Cross corresponding bites on distance start on a dedicated parody disc, which can be seen over here.
03:23
Parity
03:24
provides higher transfer rate. High availability requires a minimum of three drives.
03:38
Our raid for the key takeaway here is it's a more efficient version of Raid three, but faster
03:53
raid five. Now this one's a lot more common than, uh, the two through four
03:58
distributes parody along with the data and requires all drives that one to be present to operate.
04:03
So we have some error control here, so we have.
04:06
So if we have five, we have four discs.
04:10
Ah, we can have one of these dis fail
04:15
and we won't lose any data because the parody spread out. So you want to replace that disk? But so this will appear is one big diss. But since the parody has spread out among it, we could lose a disc
04:26
and not lose any data. It can reconstruct the law. Austerity Lost data based off the parody spread between the other disks.
04:40
Out rate sixes, block level striping with double distributed parody
04:45
distributed parody along with the data and can operate without the two failed drives.
04:49
Building upon the same concept to rate five requires minimal Fordice.
04:55
This a good solution for critical high availability applications
05:00
on this is ah, raid zero plus one where we're saying stripes sets in a marriage set. So we talked about rate zero and raid one being stripes
05:10
in mirrors. And now we're combining the concept of stripes and mirrors were not doing parody. So we're doing here is we have
05:17
we're marrying to raid zeros.
05:21
So say we have four deaths
05:27
here,
05:30
so we have four days so we can take to disk and create a stripe.
05:33
So now that's bigger. So we get some faster right performance, take the other two dis
05:40
and create a stripe,
05:42
but that first, that first rate is now going to be married
05:46
to the other raid because
05:47
they're joined together by a raid, one which is a mirror at the top.
05:53
So we're marrying.
05:56
So if you think of this as we're marrying
05:59
to striped drives,
06:01
so we're marrying to raid zeros.
06:05
So we do have some redundancy here because they were doing a mirror of the two stripes
06:15
s o. The rate continues to operate with one or more dries, fail in the same mirror set.
06:20
But if dries fail on both sides and mirror the drive on the raid system is lost, the data on the raid system is lost.
06:27
So it's kind of giving you security
06:30
in raid zero. It gives you some of the advantages of strike by Miriam. But if you lose ah, drive and both of these stripes, then you lose everything.
06:44
Uh, four must have even numbers like example. Two sets of
06:46
two
06:48
s so we can add that up. Two sets of three sets of four.
06:58
Yes. Then we go the other way around. We go raid one plus zero.
07:02
You hurt your head yet?
07:03
So we're gonna create a stripe of two mirrors.
07:13
This provides this consist ain multiple Dr Loss. As long as no Meryl lose. All strive. So
07:18
were these two are mirrors in these two are mirrors and their sink together. So
07:25
you have to lose a lot of hard drives. How many do you have to lose again?
07:30
Yeah. So unless
07:30
one of these lose all their hard drives,
07:34
we're still while weaken redundant. But we're still getting the advance of a larger just space.
07:44
So do her door. Redundant methods, complete loss of one array is survivable.
07:53
So the most common ones
07:56
that kind of highlight with more details. The rate zero striping where we're taking two drives and make it two or more drives and making them one big drive.
08:03
Um, no redundancy in that, but also has a faster
08:09
are
08:09
right time.
08:11
The raid one is mirroring where we're gonna take two or more at least two disc. Make them identical each other faster. Read time because you have to drive frying the same information.
08:22
Raid five allows you to have a stripe. But because of the parody checking on all the data, you can move lose an entire drive and still maintain all your data.
08:31
You can rebuild the new drive into it
08:35
and one plus zero,
08:37
which is the mirrored in a set in a striped set providing high redundancy.

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