raid help

[fafa21]

hey i really don’t know much about raid so could some one explain to me how it works and what it dos also i have a 160 gb hard drive and a 250 gb could i use them in raid .

thanks

[rick22]

depends what kind of raid your wanting to use..you can RAId those two drives to gether but you will only get to use 160gb of the 250gb on the second drive

[freaksavior]

i love wiki http://en.wikipedia.org/wiki/RAID

i don't mean to be rude, but try googling what your looking for first. typically you can find it in about 15 sec with a google search

[DanTheBanjoman]

RAID is a way to have disks work together, mainly to offer some safety for your data. (by either mirroring or parity)

The techkids here commonly use it for performance though, which RAID0 represents. (technically it isn't RAID though, due to the lack of redundancy)

RAID0 basically splits (stripes) data so 2 disks are used at once, think of writing a 1GB file, half gets written to one drive half to another which results in double the performance. Of course this is oversimplified but that's what it does. Of course if 1 drive crashes you lose all data since you miss half the file.

RAID1 mirrors all data, it writes the same data to both drives, ie if a drive fails the other takes over.

RAID2 is not used, it requires tons of drives and does some ECC stuff which is built into drives nowadays.

RAID3,4 and 5 basically use a drive for parity, the difference is doing it at bitlevel or not and whether to use 1 disk for parity or putting it on all drives. Exact differences aren't relevant since your cheap controller won't support 3 or 4 and RAID5 is more common anyway.

RAID6 is RAID5 with 2 parity disks, you can't afford a controller that does that nor is such a thing useful for you. (it's really rare that 2 drives in an array fail at once, if they do it's caused by something that took down the whole system anyway (power surge or whatever) in which all drives are screwed anyway.

RAID7 is used by a single company, not sure what it does nor which company it was, again you can't afford nor need it anyway.

There are also some ways to combine multiple RAID levels, ie creating an array of 2 or more other arrays, these are 10, 01, 50 etc. They require more drives as well.

Can your drives work in RAID? Yes they can, it's not recommended though. You should use identical drives for best performance.

[fafa21]

i gess i dont want to do raid any more but i have this 2 hard drive how can i use bolth of them at the same time

[rick22]

are they IDE or sata? either way just throwm them in there if you have the extra connections available and away you go

[fafa21]

they are sata

[Scheich]

software raid is nice as long as your using the exact same mobo. when your mobo dies, or your switching it for something new, all your data will become unaccessible. so its more like a high risk gamble, are u upto it ?

[CrAsHnBuRnXp]

I would also like to add that RAID (whether its 0, 1, 5, 0+1 w/e) is not a backup solution. In fact, you need to backup more often. When you RAID two or more drives together, you actually double (for two drive triple for three, you get the idea) your chances of having a hdd die on you.

Again, neither RAID array is a preventative from doing regular backups. Backups are still highly recommended in case of an unforeseeable event.

[k0rn_h0li0]

hmm how can you setup a backup drive?

so if i'm using pata/ide to connect onboard what raid is it in?

and if i'm using sata what would that be in?

[CrAsHnBuRnXp]

Originally Posted by k0rn_h0li0

hmm how can you setup a backup drive?

so if i'm using pata/ide to connect onboard what raid is it in?

and if i'm using sata what would that be in?

You setup RAID on both SATA and IDE as you normally would. They both can do all RAID arrays. You can only assign a RAID array to a set of hard drives that the motherboard supports. Same goes for a RAID controller.

Example, both IDE and SATA hard drives can do RAID, 0, 1, 3, 5, 10, 0+1, 50, etc.

You still have to back up your data to a CD or DVD or a separate hard drive to have a hard copy of it.

[k0rn_h0li0]

oh okay so you can set it up to any raid but the more you use the more likely you might lose the hdd. interesting thanks for the knowledge. although i wonder how can i back up that much information XD

[CrAsHnBuRnXp]

The more hard drives you use in the raid array, the more likely you are to have a hard drive fail. Pending on which RAID array you lose, you may be able to lose a drive or two. With RAID 0, you can afford to lose any drives as everything that is contained on those hard drives in the array, will be gone.

The only thing you back up are what you normally would in a non RAID array. (eg Music, pictures, documents, etc. Not the drive as a whole)

[ex_reven]

Originally Posted by CrAsHnBuRnXp

The more hard drives you use in the raid array, the more likely you are to have a hard drive fail. Pending on which RAID array you lose, you may be able to lose a drive or two. With RAID 0, you can afford to lose any drives as everything that is contained on those hard drives in the array, will be gone.

The only thing you back up are what you normally would in a non RAID array. (eg Music, pictures, documents, etc. Not the drive as a whole)

I think its important to realise that a drive is not more likely to fail just because it is in raid. It isnt being used any more than it would have been without the raid setup. So if your drive fails in a raid, it would have failed outside of raid anyway. Though the contents of the other disks in the raid would be preserved had they been left as invidual drives.

If your an average user or gamer you should be able to chuck your stuff onto dvds easily for backup. Eg I have a dvd for software, a dvd for music, and another dvd for my documents.
Its only when you have a large number of files that it becomes difficult (and/or more expensive) to raid.

[DanTheBanjoman]

Originally Posted by CrAsHnBuRnXp

Pending on which RAID array you lose, you may be able to lose a drive or two.

Only RAID1 with more than 2 drives allows for failure of more than 1 disk at the same time. Other than that you'd need RAID6 (not an official RAID level) or RAID 50/51 (mix of RAID 5 and 0/1). Additionally hot spares could help, though they do not allow failure of 2 drives at once.

As for harddrive failure increasing with RAID, that's exactly why RAID exists, to protect against harddrive failure. It decreases the chance of losing data. (RAID0 isn't actually RAID for exactly that reason, it offers no redundancy)

wait, if a raid 0 system fails, can you format the living drive back to normal, or are they both gone permanantly?

[tigger]

Yes you can still use the living drive singly.

[man114]

I've got two 250GB SATA drives running in RAID0.

As with anything, just back up everything of importance to some other sort of hard drive if you're worried about losing it. Externals are fairly cheap. I've got a lot of stuff backed up on an old Seagate Elite 47 SCSI drive in another computer. In this case, due to the size of the drives I've got an external Western Digital 250gb thing I picked up for virtually free at one of those CompUSA sales last year.

I've messed around with RAID before, I've got an old PCI card for it somewhere, don't even remember where I got the card either.

I've found that while this looked good on paper and benchmarks well, the real world performance difference you notice is sometimes minimal unless you do something that noticably requires a large amount of hard drive read/writes on a regular basis.

My ancient non RAID Athlon Tbird would boot to XP just as fast as this computer will, only had a 100GB 7200rpm drive and 40gb 7200rpm drive, both standard IDEs.

I think loading the OS is a ram-based operation, not harddrive

[DanTheBanjoman]

Originally Posted by bassmasta

I think loading the OS is a ram-based operation, not harddrive

You think wrong.

?>.> I've found faster ram to help load OS more than a harddrive

[DanTheBanjoman]

Originally Posted by bassmasta

?>.> I've found faster ram to help load OS more than a harddrive

Replace your harddrive by a ramdrive and see the difference.

[man114]

I'd venture to say it is a combination of both, if you have a system low on ram the computer will be writing to the hard drive for its page file, slowing down the time it takes to boot, if you want to see this happen take a few RAM sticks out of your computer and put some small chips in if you've got some floating around. The computer will likely be slow to load, regardless of what speed the hard drive is.

A couple of years ago my friend at work gave me an emachines computer, think it was a Celeron 433 or something, still not a terribly slow computer at the time in terms of processor speed. Her sister had bought a new computer because it was too slow. I booted the computer up, which took roughly 10 minutes. Checked to see the amount of RAM and it was 32MB. Even at the time the computer would have been new that was a low amount. I put a 128 in and the computer booted about twice as fast, and operated so much faster you'd have thought it was a different computer. I sold it off and made a few bucks.

As far as the hard drive's influence on the boot process, take a computer which has plenty of RAM for it's applications. Then take an old slow hard drive and throw it in for kicks (try to find one of those 1.7gb 4500 RPM Seagates if you really want to see it crawl). Watch your computer drag along.

Other factors include the programs you load at startup, the more you load the longer it takes to boot.

I've always been a believer in having fast hard drives. Before it got terribly outdated for even a few years afer I built it, when I'd go to a store and see a budget machine that couldn't load programs as fast as my old Athlon system because the manufacturer cut corners and used cheap slow hard drives (when they were running 5400rpm drives as opposed to the 7200rpm drives I used), knew the money was well spent.

From any standpoint I should be better off on this computer RAID0 and 3GB ram, I'm sure as time drags on the benefits of the fast hard drive system and RAM will become more apparent.

[DanTheBanjoman]

Sure, when RAM is being the bottleneck it matters a lot. Then again in that case all parts matter, try booting Vista on a 486. Fact is, harddrives are the biggest bottlenecks in most systems.

[ex_reven]

Originally Posted by DanTheBanjoman

Sure, when RAM is being the bottleneck it matters a lot. Then again in that case all parts matter, try booting Vista on a 486. Fact is, harddrives are the biggest bottlenecks in most systems.

Agreed.
After all, data has to be written into ram from the hard drive. So regardless of the speed of your ram, it can only get the data as fast as the hard drive will access it.