raid?

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RyanL

Gawd
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Sep 18, 2003
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Ok i am getting two 250 Gig sata 7200 RPM hard drives...should i raid them? If so what config?
 
We need to know the mission for these drives before we can recommend a RAID level. Will they be storing personal data? Working on content creation? Being used for 'storage'? Do you need all 500GB, or is 250GB enough? There are more questions to answer, but these immediately spring to mind. Provide as much info about what you want the drives to do as possible and we'll help you out.
 
Basically well mainly be storage...all personal data of mine is backed up to a network hard drive. These are going a gaming machine...so i want the quickest load possible...i would liked to use all 500 GB inless there is a super speed increase in not....i know i can mirror them etc... but they will basically be used for mass storage and gaming ... web design dreamweaver, possiable DVD storage also.
 
Anybody have any insight on DreamWeaver disk access patterns? It may be a workstation type task that would beneift from *GASP* RAID-0. The DVD work will also benefit from RAID-0, particularly if you have a high GHz P4 to hack through encoding work and take advantage of the extra disk throughput.

Game level loading, as pointed out many times before, stands little to nothing to gain from RAID-0, but your other tasks may offset the additional risk of failure. Get Maxtor DiamondMax10s, Hitachi 7K250s, or Seagate 'Cuda 7200.8. None of these drives will be weak at loading levels, but by far the best storage system for your gaming needs is a WD740GD Raptor, if you can afford what one costs. Then put the 250GB drives as two independent volumes or if you're feeling adventuorous and have a solid backup strategy, RAID-0. However, if you can't afford the Raptor and the 500GB, setup the two 250GB drives as separate volumes, run OS, programs, and games off of one, your DreamWeavear and DVDs on the other. Good Luck!

BTW, I live in Greenwood, and a good portion of the family is in Seymour in Jackson County. So I'm quite familiar with the country south of Indy :)
 
I am located in Martinsville about 25 min south of Greenwood...i use to live in Whiteland which is 5-10 min from Greenwood.

So what is the likey hood of raid-0 failing?
 
Mathematically, twice that of single drive, as if either drive goes, all data is lost. However, the practical effect is ovbiously harder to quantify. Some people have RAID-0 sets that last for years. Others have them fail in mere months. As always, YMMV, and backup is an absolute necessity if you are going to use RAID-0. I just can't recommend Striping without a backup strategy in place.
 
So before installing windows...i would use onboard raid setup correct? Setup my SATA raid...boot windows installer... use the floopy drivers...and then go from there? Are there any options that i need to know in the setup sector size etc?
 
but they will basically be used for mass storage and gaming
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Then RAID 0 is not something you should be doing here.


backup is an absolute necessity
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It's impossible to stress how important backup is if you don't want to lose your data. Even if you're not using RAID 0 and thus greatly increasing your likelyhood of data failure. It's not just the increased likelyhood of drive failure nuking all your data - which is exactly what it'll do when one of the drives develops issues, which sooner or later will happen. With one drive, at least you should have a little leeway to get off any data you didn't already have backups of. With RAID 0, one of the drives starts dying, the array and all your data are GONE. But that's not all, it's quite possible that something can happen to screw up the array without one of the drives being bad for no other reason than because it just booted funny that day. RAID 0 doesn't help for gaming, and if you want it for data storage that's just completely contradictory.
 
RAID-0 will let you use all 500gigs.

and since you say:
"all personal data of mine is backed up to a network hard drive."

I don't think there is any problem using RAID-0, at all.
Just make sure you can live with loosing anything not backed up.
To be completely clear, there is twice the chance for *data loss*, NOT twice the chance for *drive failure* with RAID-0. Many people mix those up.
 
RyanL said:
So what raid should i run if i want to use all 500 gigs?
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They make this thing called JBOD that does exactly that, but it's not exactly RAID either, it's Just a Bunch Of Disks.
 
One vote for JBOD here.

I wouldn't bother with RAID-0.

As for Dreamweaver: Not much drive access... Thank God. Mostly CPU and memory overhead (A LOT of overhead.) Fortunately, it's not one of those apps that constantly accesses the drives. Even if you have a bunch of application extensions, those all load up on initial start-up.

*sigh* Dreamweaver. Like Windows, a necessary evil. :(
 
Depending on implementation, JBOD has the same likelihood of data loss as RAID-0, as one missing drive takes out the whole array IIRC, at least in many implementations.

Given the new information that's come out, I'd go with a pair of single drives - you can mount one in a subfolder of the other to get 500GB on one drive letter, and if one of the drives goes out, there data on the other is still ok.
 
Since JBOD isn't striped, sometimes you can get some of the data off a broken array. Sometimes you're just screwed. RAID 5 would still be the best choice if he wants a large unitary array, but JBOD's at least a little safer than RAID 0.

NTFS folder mounting is a great way to go if it'll work for you. You don't have the extra hardware RAID 5 would take and you don't have the greatly increased risk that other things would cause.
 
DougLite said:
Depending on implementation, JBOD has the same likelihood of data loss as RAID-0, as one missing drive takes out the whole array IIRC, at least in many implementations.

Given the new information that's come out, I'd go with a pair of single drives - you can mount one in a subfolder of the other to get 500GB on one drive letter, and if one of the drives goes out, there data on the other is still ok.
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I personally have never seen that, nor understand how you risk all data integrety if one drive dies.. Because it is "Just a Bunch Of Drives," similar to having multiple Master and Slave drives on an onboard IDE controller. I know you interjected the disclaimer that this may happen in "some implementations," so I'm certainly not going to say you're wrong. I've just never seen it.

I have one of those SuperMicro cases with the hot-swap SATA drive bays. I use it as a Production Server so each of three drives has a different image. If I need an image and don't want to pull it through the network, I just slide out the drive (I love how SATA is hot-pluggable) and hook it up to my build. When I'm done, I just slide the drive back into the front of the case and it grabs a drive letter.

I do this because we roll out machines with software installed and the source files for the software is on the drive as well. When the software is updated (which is twice a month it seems!) we copy the source files over to the Production Server and then copy that over to each of the other drives in the JBOD. That way, all of our source images are in one place, constantly updated and can be accessed via network or by sliding out a drive.
 
jonnyGURU said:
I personally have never seen that, nor understand how you risk all data integrety if one drive dies.. Because it is "Just a Bunch Of Drives," similar to having multiple Master and Slave drives on an onboard IDE controller. I know you interjected the disclaimer that this may happen in "some implementations," so I'm certainly not going to say you're wrong. I've just never seen it.
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Yes, but what happens to a file that is partly on two drives in a JBOD, if one of those drives goes out? There is no redundant data to reconstruct such a file - all members must be present and online for the array to be operational.
 
Then as far as that file goes, you're screwed.

With RAID 0, you're screwed by default, instead of having the possibility of getting some of them out on JBOD. Neither of them is something that's a very good idea though. JBOD is at least a bad idea, instead of being the data equivalent of playing russian roulette like RAID 0.
 
ashmedai said:
Then as far as that file goes, you're screwed.

With RAID 0, you're screwed by default, instead of having the possibility of getting some of them out on JBOD. Neither of them is something that's a very good idea though. JBOD is at least a bad idea, instead of being the data equivalent of playing russian roulette like RAID 0.
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And I'd presume, that if a JBOD failed, it would wreck the file system, and you would have to run a low level recovery, and hope fragmentation was at a mnimum, in order to recover data off of remaining drives.

As for the Russian Roulette example, RAID-0 is like playing with two rounds loaded...
 
DougLite said:
Yes, but what happens to a file that is partly on two drives in a JBOD, if one of those drives goes out? There is no redundant data to reconstruct such a file - all members must be present and online for the array to be operational.
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Ok. So you're describing an implementation of JBOD that is more like RAID-0 than what I use JBOD for. On my Promise FastTrak S150 SX4, the drives each have their own drive letter and primary partition. There would be no reason for a file to span across two drives. If I were going to do that, I'd just go ahead and set the card up for RAID-5 and gain the fault tolerance, but because I don't need fault-tolerance since I've got 20 machines a week crossing my desk with all of the same data on them, I use JBOD.

So there's an implementation of JBOD that makes the drive one drive letter, one partition and doesn't give you the speed benefits of RAID-0? What a waste.
 
jonnyGURU said:
So there's an implementation of JBOD that makes the drive one drive letter, one partition and doesn't give you the speed benefits of RAID-0? What a waste.
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Correct, that's the JBOD I was referring to, and you are right that it is a very bad idea. Your system sounds like single drives that just happen to be attached to a RAID BIOS, and that's the only association with RAID they have.

My understanding of JBOD is spanning one file system across many drives to make them one gi-f'ing-normous drive with one drive letter, and no fault tolerance. Many people out there want to take a bunch of drives of various sizes and make them one big drive, and JBOD is the only way to do it and achieve the capacity of all of the drives put together. As you, I and Ashmedai (hey that rhymes :D) have pointed out, it's a very bad idea.
 
I can't remember when I started using raid 0, though I do remember the harddrives being WD Caviars. But I've been using raid 0 with two maxtor d740x's since 2001 with various cards and motherboards. I have NEVER experienced data loss and have NEVER had the drives fail. I was still using the drives until yesterday when they were replaced with Samsung 1614c's.
 
NeonFlak said:
I can't remember when I started using raid 0, though I do remember the harddrives being WD Caviars. But I've been using raid 0 with two maxtor d740x's since 2001 with various cards and motherboards. I have NEVER experienced data loss and have NEVER had the drives fail. I was still using the drives until yesterday when they were replaced with Samsung 1614c's.
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We're not saying RAID 0 is going to explode the second you install it, just that it does nothing for most people at all in exchange for a much higher risk level. Why take that risk in exchange for nothing? It has its place, unfortunately a great many people have gotten the false idea that RAID 0 will always make whatever they're doing run faster.
 
ashmedai said:
Why take that risk in exchange for nothing?
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The popular notion around here now seems to be that RAID-0 doesn't net you any benefits unless you're doing video editing. That's utterly false. Extracting files, launching games (not loading levels it seems), launching apps. It's simply faster. If you have two identical disks, just do it. If you hook your disks up separately, a drive dies, you loose half your data. Who knows which half. Was it your "important stuff" or not? Who knows. You RAID-0 your disks, one drive dies, you loose all your data.

You're hurting either way. Just backup anything you don't want to loose, and RAID-0 your disks. Win-Win.

End of story.
 
v3rt1g0 said:
The popular notion around here now seems to be that RAID-0 doesn't net you any benefits unless you're doing video editing. That's utterly false. Extracting files, launching games (not loading levels it seems), launching apps. It's simply faster. If you have two identical disks, just do it. If you hook your disks up separately, a drive dies, you loose half your data. Who knows which half. Was it your "important stuff" or not? Who knows. You RAID-0 your disks, one drive dies, you loose all your data.

You're hurting either way. Just backup anything you don't want to loose, and RAID-0 your disks. Win-Win.

End of story.
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Yeah.. But then the "do things half ass" aspect comes into question. I don't like just "throwing money" at computers, but if you want to do RAID-0 right, do it up RAID 0+1 with FOUR drives instead of just two. ;)
 
I think RAID 0+1 is silly. The costs double. Same as Raid 1.
Best thing to do is buy one extra drive to stick in your computer, or stick it in a network server, and setup Ghost (or whatever) to make automatic backups, so you don't "forget" (read- slack off).
 
Mmm....RAID 50...need a more expensive controller than I'm willing to bounce for though. Especially as it wouldn't do shit for me. What's it going to do, play back the file faster? Pffft.
 
How many hdd's can u have when u make RAID? And Does the hdd's need to be exact the same ones when making Raid?
 
LionKinG88 said:
How many hdd's can u have when u make RAID? And Does the hdd's need to be exact the same ones when making Raid?
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However many the controller supports, minimums according to the level of RAID you're implementing, some also require other things like an even number of drives or whatnot.

It's a good idea to use the same drives. You can get away with not, but you should read up on it first especially if you're going to do that.
 
LionKinG88 said:
How many hdd's can u have when u make RAID? And Does the hdd's need to be exact the same ones when making Raid?
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RAID-0 = At least 2 drives. Even number.
RAID-1 = At least 2 drives. Even number.
RAID 5 = At least 3 drives.
RAID 0+1 or 1+0 = At least four drives. Multiple of four.
RAID 5+1 = At least 6 drives. Multiple of two.
JBOD = 2 or more.
 
jonnyGURU said:
RAID-0 = At least 2 drives. Even number.
RAID-1 = At least 2 drives. Even number.
RAID 5 = At least 3 drives.
RAID 0+1 or 1+0 = At least four drives. Multiple of four.
RAID 5+1 = At least 6 drives. Multiple of two.
JBOD = 2 or more.
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Incorrect.

RAID-0, at least two drives, any number above that up to the limitation of the controller BIOS.
RAID-1, Same as zero
RAID-5, Guru did get this one right
RAID 0+1 4 drives, additional drives in pairs.
He also got 5+1 and JBOD right. How hard is it to get JBOD wrong? :D

Not trying to flame/put down/etc, but the right info needs to be out there. BTW, I admire Johnny's m4d PSU sk1llz. So it's nothing personal about him.

Also, for best performance, drives should be the exact same make/model/size, ideally the exact same firmware. An array will run at the highest common speed and capacity.
 
DougLite said:
Incorrect.

RAID-0, at least two drives, any number above that up to the limitation of the controller BIOS.
RAID-1, Same as zero
RAID-5, Guru did get this one right
RAID 0+1 4 drives, additional drives in pairs.
He also got 5+1 and JBOD right. How hard is it to get JBOD wrong?
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You're right about RAID-0. Could be any number of drives 2 or greater that you would want to stripe. My bad.

You're wrong about RAID-1, though. Has to be an even number as each drive installed has to have a mirror drive, therefore it is not the same as RAID-0 as RAID-0 you can have an odd number of drives. What happens if you have three drives? Half of drive two and all of drive three is going to mirror all of drive one and half of drive two?

That's why RAID 0+1 follows the same rule, although it seems I got that half wrong. You could have a three drive RAID-0 and then mirror it with anohter three dirves, and six is not a multiple of four.

Also, for best performance, drives should be the exact same make/model/size, ideally the exact same firmware. An array will run at the highest common speed and capacity.
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Actually, an array will function at it's LOWEST common denominator. Not highest. Although I'm sure that was just a typo. ;)

Thanks for pointing out that I'm "incorrect" as if I'm "mostly incorrect" even though I'm "mostly correct." I'll make sure to remember that. ;)

Not trying to flame/put down/etc, but the right info needs to be out there. BTW, I admire Johnny's m4d PSU sk1llz.
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I don't have "mad power supply skills." I just got pegged into that hole because I have a power supply tester. I've got a two-year old too, but I don't have mad toddler skills. ;)

...it's nothing personal about him.
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I know... But I had to say something just the same. ;)
 
Lowest common is used because you're simplifying a mathematical expression and want to find the "most simple" way that it can be stated. Highest common would actually be the case with RAID, because it's using the highest size/speed shared in common between the installed drives.
 
ashmedai said:
Lowest common is used because you're simplifying a mathematical expression and want to find the "most simple" way that it can be stated. Highest common would actually be the case with RAID, because it's using the highest size/speed shared in common between the installed drives.
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If I have two hard drives, one faster than the other, and they're striped RAID-0... The array is only going to run as fast as if I had two of the slowest drives in the array. Lowest common denominator.

If I have two hard drives, one 80GB and one 120GB, and they're a mirrored RAID-1... The drive capacity is only going to be 80GB. Not 120GB or anything between 80 or 120. Lowest common denominator.

I don't think we're talking about RAID versus no RAID where RAID would be the highest common denominator versus none at all, because to discuss that would be a moot point at this juncture.

Please explain to me how I'm missing the point here?
 
What we mean by highest common is this, as another example:

Say you mix PC2700 and PC3200 RAM modules. Barring a weird chipset bug that makes them not work at all, they will run at PC2700, not arbitrarily run at PC2100. That's what highest common speed means. They will run at the best speed and capacity that is common to all drives. If you RAID-1 an 80GB and 120GB, you get 80GB - the highest common capacity. That's what we mean.

Also, on RAID-1, it would be conceivable to have three drives mirrored with the same data, thus extending fault tolerance to allow two drives to go out without data loss. This is also the fastest RAID configuration for loads that are 90%+ reads of an extremely short and random nature, as a smart RAID controller can allow each spindle to service different read requests individually, rather than tying up all the spindles for one request at a time with striping. Obviously, this doesn't work for writes, as athe writes go to all of the spindles at the same time.
 
DougLite said:
Also, on RAID-1, it would be conceivable to have three drives mirrored with the same data, thus extending fault tolerance to allow two drives to go out without data loss.
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Hmm ... certainly won't question your wisdom I've just never seen a RAID 1 Array that was comprised of anything other that two phyical or logical disks.
 
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