OS on RAID-0, Should I?

[spoon805]

I've been reading the forums and searching on google, but can't come to any conclusion.

I'm running XP Pro and would like to install it on a RAID-0 setup.

Is this wise?

What problems, if any, have people run into (besides the lack of redundancy) of putting one's OS drive on RAID?

Are the benefits of such a setup worth the trouble?

The array would be two 9 gb scsi ultra 160 on a mobo intergrated adaptec controller. All my cherished data (mail, docs, projects, photos, mp3s, downloads... anything nonreplaceable) is being stored on two standalone drives not in RAID (total of 27 gb).

Thanks

 

[DAPUNISHER]

I run XP pro in RAID0 with no issues and excellent performance so I'm all for it, especially since you've been wise enough to store your critical data elsewhere since that's the one drawback of RAID0.

 

[SemperFi]

WinXP Pro on raid 0 here and loving it. Ditto on the backup.

I am keeping an eye out for a good sale on 2 maxtor 80 Gig. I want to make raid 0+1. I just have to flash my motherboard.

 

[Deeko]

I'm running WinXP Pro, highPoint raid controller built into my motherboard, I've got dual 80GB Maxtor drives running, its sweet, well worth it. People are afraid fo RAID because they think "oh if one drive dies you lose all your data".....yea.....it would be the same way if you were only running one drive and that died.

 

[Alchemist99]

Originally posted by: Deeko
I'm running WinXP Pro, highPoint raid controller built into my motherboard, I've got dual 80GB Maxtor drives running, its sweet, well worth it. People are afraid fo RAID because they think "oh if one drive dies you lose all your data".....yea.....it would be the same way if you were only running one drive and that died.

True but your odds of losing a drive are increased, but its worth it i have four hdd in two raid 0 config and my os on a seprate hdd from them.

 

[SemperFi]

Deeko, LOL

I didn't even think of it like that. But it has been a long time since I have only had one drive in a system.

 

[CurtCold]

Originally posted by: Deeko
I'm running WinXP Pro, highPoint raid controller built into my motherboard, I've got dual 80GB Maxtor drives running, its sweet, well worth it. People are afraid fo RAID because they think "oh if one drive dies you lose all your data".....yea.....it would be the same way if you were only running one drive and that died.

That's soooo true Deeko. Almost every hardware site groans and mubles over this issue. I don't think it's worth it, I do. I have a 30gb maxtor that I store all my critical software on just like you do, and 2x120gxp 60GB Ibm's in Raid 0 with promise raid controller. I love RAID 0 for gaming. Also might want to make sure you have 512MB of Ram spoon805. I had 256 when I first installed the raid, and when I upgraded to 512, I noticed a big difference in performance.....

 

[spoon805]

I got it under control

Dual 733, OR840 chipset MOBO, 512mb RDRAM 800 ECC.... I have no idea what my SCSI controller is though.

Essentially its a Dell precision workstation 420. I was orignally wanting sell this, but i'm going to squeeze another year or two of enjoyment out of it before it becomes a server of somesort.

 

[SpideyCU]

Finally, people who isn't saying something stupid like "I can't stand the thought of anyone out there running RAID-0, it's so unreliable". Some folks make it sound like just by the fact that you're running RAID-0, one of the drives is more likely to die. Phhbt. If you're not stupid about it, it's a great performance booster for minimal cost.

 

[spoon805]

Thanks for all the support guys.

I'm new to RAID, so this is rather newbie, but what block size should I set my config for housing an OS?

 

[SpideyCU]

I'll put a vote for 64k - that's what I've always used. I'd actually like to hear if someone has reason for running @ a different stripe size. I'm curious, myself.

 

[Lucky]

Originally posted by: Deeko
I'm running WinXP Pro, highPoint raid controller built into my motherboard, I've got dual 80GB Maxtor drives running, its sweet, well worth it. People are afraid fo RAID because they think "oh if one drive dies you lose all your data".....yea.....it would be the same way if you were only running one drive and that died.

Except the odds are doubled you'll have a failure. I run RAID-1.

 

[CurtCold]

Another vote for 64k. Just base the size on what you do the most. IF your doing Autocad, or PhotoEditing, you'll prolly want a larger stripe size, if you just have mp3's and such, then maybe smaller. I chose 64k, because it's in the "middle" so to say, I have mp3's, and games, and photos, so I just wanted to get the best performance all around.

RAID rules in games. When your loading that huge map in 1942, you'll notice the raid kickn' in.....

 

[Ilmater]

I think you realize the problems of the lack of redundancy, so feel free to do what you like. Enjoy your RAID setup.

As far as block sizes go, I would suggest 64k as well, but the best is to try for yourself and see what suits YOUR performance needs.

 

[MrGrim]

For whatever it's worth, I went from RAID0 to RAID1.

BTW installing your O/S on your RAID0 array reduces the performance of the array.

 

[NOX]

Originally posted by: MrGrim
For whatever it's worth, I went from RAID0 to RAID1.

BTW installing your O/S on your RAID0 array reduces the performance of the array.

Maybe true but it still beats a single drive any day.

I've been running RAID0 for almost two years now; I've heard it all, all the reasons why I shouldn't run RAID0 (mainly because it provides no safeguard). However, like a few others have said, RAID0 is like running a single drive.

Once you accept the fact that backing up your data whenever possible is the only true safeguard, you will be on your way to enjoying the performance benefit of RAID0.

Lets also not kid ourselves and remember that RAID0 mainly offers performance. Some will say they don?t see it, or that it?s not much faster then their single drive setup. Well, I can personally say that RAID0 made a big difference to me and that?s all that really matters right? If you are pleased then you have accomplished your goal.

Just for the record I use a 64k stripe.

Good Luck!

 

[dszd0g]

rAID 0 runs just fine on an OS. If you do regular backups I don't see a problem with it. That said, I wouldn't do it with IDE drives. I'd consider doing it with SCSI drives (which in general more reliable). However, most of what one does on a HD is read and RAID 1 gets decent read performance (not as good as rAID 0) but with increased data redundancy not decreased.

I don't agree with Deeko's one drive comparison. Sorry I don't think you will pass that one by anyone who has studied probabilities.

If A1, A2, ..., An are pairwise mutually exclusive, then

P{ U(k=1,n)Ak} = SUM(k=1,n)P{Ak} for n >= 2

Thus if the probability of 1 drive failing this month is 1%, the probability of either of two drives failing this month is 2%. Thus you just doubled your chance of a failure.

The probability of both drives failing is 0.01% for RAID 1 if one assumes that the events are independent P{A intersect B} = P{A}P{B}. In reality, one drive failure may very well be related to another in the same system. If it was heat related the other drive may be exposed to higher than ideal temperatures too. If the power supply provided bad power to one drive it probably provided bad power to the other. In this situation one would have to know what the probability if one drive fails that the other drive fails and then apply Bayes' Rule. Let's say that in a given system if one drive fails, the probability of another drive failing increases to 6%. Then the probability of both drives failing is: P{A intersect B} = P{B|A}P{A} = 0.06 * 0.01 = 0.06% which is probably a little more accurate of a RAID 1 set-up relative to single drive and RAID 0 with those absolute numbers meaningless as I pulled them out of my....

 

[Sunner]

I'd definately prefer a RAID-1.

You'll get the increased read performance, though your write performance will remain the same as with one drive.
But really, what most people want is increased read performance, after all you only install something once, then read it alot.

 

[Pariah]

"I'm running WinXP Pro, highPoint raid controller built into my motherboard, I've got dual 80GB Maxtor drives running, its sweet, well worth it. People are afraid fo RAID because they think "oh if one drive dies you lose all your data".....yea.....it would be the same way if you were only running one drive and that died."

That's only true if you have one drive. If you have 2 drives, that's a bogus arguement. If you use 130GB of that 160GB array and you lose either drive, you lose everything. You use those 2 drives seperately, and the most you can lose from a dead drive is only 80GB of your 130GB of data. If you're only using 40GB of that 160GB array then why are you using an array that large in the first place? Get a load balancing RAID 1 card and gain the benefits of RAID 0 read speeds with greatly increased data protection provided by RAID 1.

 

[ssanches]

Originally posted by: dszd0g
rAID 0 runs just fine on an OS. If you do regular backups I don't see a problem with it. That said, I wouldn't do it with IDE drives. I'd consider doing it with SCSI drives (which in general more reliable). However, most of what one does on a HD is read and RAID 1 gets decent read performance (not as good as rAID 0) but with increased data redundancy not decreased.

I don't agree with Deeko's one drive comparison. Sorry I don't think you will pass that one by anyone who has studied probabilities.

If A1, A2, ..., An are pairwise mutually exclusive, then

P{ U(k=1,n)Ak} = SUM(k=1,n)P{Ak} for n >= 2

Thus if the probability of 1 drive failing this month is 1%, the probability of either of two drives failing this month is 2%. Thus you just doubled your chance of a failure.

The probability of both drives failing is 0.01% for RAID 1 if one assumes that the events are independent P{A intersect B} = P{A}P{B}. In reality, one drive failure may very well be related to another in the same system. If it was heat related the other drive may be exposed to higher than ideal temperatures too. If the power supply provided bad power to one drive it probably provided bad power to the other. In this situation one would have to know what the probability if one drive fails that the other drive fails and then apply Bayes' Rule. Let's say that in a given system if one drive fails, the probability of another drive failing increases to 6%. Then the probability of both drives failing is: P{A intersect B} = P{B|A}P{A} = 0.06 * 0.01 = 0.06% which is probably a little more accurate of a RAID 1 set-up relative to single drive and RAID 0 with those absolute numbers meaningless as I pulled them out of my....

Are you related to Dexter??

BTW, I was just about to reply with the same thing when I read your post. The thing about the probability is correct, except that I'd consider the events to be mutually exclusive. As an illustration, just because your neighbor died, does not mean your chances of dying increase. These things are mutually exclusive. And I definitely consider the same thing applying to the present case. If the power is bad, then this is automatically factored in since the probability of each drive failing is automatically decreased independently of each other... the same thing with heat and all that stuff you mentioned...

IMHO, the best and simplest way to find out the reliability of an array is to multiply the probabilities of each drive not failing.

 

[ssanches]

n/m

 

[dszd0g]

Originally posted by: ssanches

Are you related to Dexter??

Are you?

BTW, I was just about to reply with the same thing when I read your post. The thing about the probability is correct, except that I'd consider the events to be mutually exclusive. As an illustration, just because your neighbor died, does not mean your chances of dying increase. These things are mutually exclusive. And I definitely consider the same thing applying to the present case. If the power is bad, then this is automatically factored in since the probability of each drive failing is automatically decreased independently of each other... the same thing with heat and all that stuff you mentioned...

Well it depends on the cause of the neighbors death. If it was environmentally related, for example if your neighbor died of cancer the probability of you dying from cancel does increase. There are a lot of groups that monitor areas for related birth defects and deaths. So I disagree with your analogy as it isn't always true. It depends on how the neighbor dies and that has to be factored into any overall probability so the overall probability is going to increase slightly. If you heard that a neighborhood had a high cancer rate, would you want to move into that neighborhood or would you believe that the events were mutually exclusive and it was just an unlucky neighborhood?

One also has to factor age into the whole thing if one wants to be accurate. If everyone in the neighborhood is 60 or older the probability of an individual dieing is higher. If all your hard drives are 4 years old, the same thing occurs.

I have had two drives die in a RAID 5 array, the second one soon after the first. The probability of that occuring if they were mutually exclusive events is lower than winning the lottery, but I don't believe I was that unlucky. They are not mutually exclusive events. There could have been a power surge or something that caused damage to both drives.

IMHO, the best and simplest way to find out the reliability of an array is to multiply the probabilities of each drive not failing.

That only works if you assume they are mutually exclusive, which is what you assume but I disagree.

 

[Eug]

The reason people don't like RAID 0 is:

1) The likelihood of all your data being lost over two drives is higher than if you had two separate drives.
2) If one drive dies, you lose all your data, on both drives.
3) The lost data is essentially unrecoverable, unless you're willing to spend $$$$. With some effort you CAN sometimes recover some data yourself from some semi-failed single non-RAIDed drives.

Thus: If you plan on using RAID 0, then be prepared to backup religiously (although granted you should be doing that anyway).

I remember when people started doing this in droves. About 6 months later, people started to post here fairly often: "Ack! My RAID 0 setup failed and I can't read any of the data on the drives at all! What am I gonna do!!!"

But I would consider if my machine were just a gaming machine...

 

[spoon805]

This is so much bull crap. My mobo SCSI controller...the adaptec AIC-7899 may not be RAID capable! Crappy thing is that I can't be for sure, there's no documentation at the dell or adaptec site. I'm getting this notion from playing around the config util and also a few blurb on the dell forums. Anyone know anything on this controller?

:|

Thanks for the education anyways.

 

[Stark]

Originally posted by: SpideyCU
Finally, people who isn't saying something stupid like "I can't stand the thought of anyone out there running RAID-0, it's so unreliable". Some folks make it sound like just by the fact that you're running RAID-0, one of the drives is more likely to die. Phhbt. If you're not stupid about it, it's a great performance booster for minimal cost.

In theory. The problem is, every benchmark that's been run shows there's little to no actual speed advantage from running IDE Raid-0. It's something to do to say you did it, but if you're really concerned about disk speed you're better off buying an adaptec 29160 card and a 10k rpm ultra 160 drive.