View Full Version : What is RAID?
Hi there, noob here:
I understand that RAID is to do with hard drives and as far as I can tell, it is a way of linking two together. But what exactly is it, how does one achieve it and what are the main benefits/pitfalls associated?
Many thanks
AaronWHUFC
22-01-10, 19:35
Pretty straight foward.
You hit your motherboards specific key combination at boot up and you get taken to the "Raid Bios" where you can configure it.
Then when installing the operating system it will be seen as one drive.
Raid 0 is fure pure speed, know as a striped array, where both drives are "joined" and in you get the speeds of both drives, more or less. There is no redundancy as data is spread across both drives.
On the other types of RAID the data is on one drive, then backed up onto the others.
More info on the different types of RAID , here (http://en.wikipedia.org/wiki/RAID).
I'm guessing your after RAID 0, raw speed!:D
Thanks for the reply. I'm in the process of assembling some bits for a first time build. Basically, the plan is this. As I will be pretty cash-strapped, at first I will buy a 2TB hard disk. Then when I get some cash back in and they drop in price a bit (maybe just over a year or something like that) buy an SSD. I'd be wanting to put the OS on the SSD obviously and the 2TB would then be used to hold all films, TV, music, that sort of thing. Would those two drives then be RAIDed? Would that be of any benefit? If I RAID them does that then mean that if I have more apps and games than the SSD could hold that they could then be stored and installed on the 2TB drive? Is any or all of what I'm saying complete nonsense?
AaronWHUFC
22-01-10, 19:48
No!!!!
The lowest size/speed will be used. So a 30GB SSD will reduce the other drives to 30GB too!
So only 30GB of the 2TB would be usable!
Loads of people do the same setup as you! Keep it simple, no Raid. You wouldn't notice any speed gain, just loss. An SSD is soooo fast as it is!:D
Okay, that makes sense now.
Hypothetically now, just to make sure I get it, say I had two 200GBs, one 5400 and the other 7200, would RAID0 be a good idea on them then?
AaronWHUFC
22-01-10, 20:13
Okay, that makes sense now.
Hypothetically now, just to make sure I get it, say I had two 200GBs, one 5400 and the other 7200, would RAID0 be a good idea on them then?
No because it'd be at the speed of the lower one in terms or write and read. Just stick to one drive mate!
You could put two 500GB's in Raid 0 for pure archiving. But, it'd only be 500GB of space you can use. The other 500GB would mirror the first drive should it pack up.
Like I said, stick to one drive.
Yes, that would work.
RAID 0 just distributes data across the two disks. Striping two 200GBs, regardless of their speed, would give you 400GB of storage and faster read/writes.
No because it'd be at the speed of the lower one in terms or write and read. Just stick to one drive mate!
You could put two 500GB's in Raid 0 for pure archiving. But, it'd only be 500GB of space you can use. The other 500GB would mirror the first drive should it pack up.
Like I said, stick to one drive.
I think you're thinking of RAID 1 there mate, where the drive is mirrored.
With RAID 0, should a drive fail, the other drive will also be rendered useless as the data is spread across 2 drives.
RAID 1 protect you from disk errors... but should the data on one drive become corrupted (and the drive remain functional), that corrupted data will be copied across.
AaronWHUFC
22-01-10, 20:25
Yes, that would work.
RAID 0 just distributes data across the two disks. Striping two 200GBs, regardless of their speed, would give you 400GB of storage and faster read/writes.
For pure archiving, it's not worth it.
No because it'd be at the speed of the lower one in terms or write and read. Just stick to one drive mate!
You could put two 500GB's in Raid 0 for pure archiving. But, it'd only be 500GB of space you can use. The other 500GB would mirror the first drive should it pack up.
Like I said, stick to one drive.
I don't plan on doing this, was just trying to find a hypothetical example to help me understand it further.
Thanks for the advice, will just stick to using the 2TB drive, then when I can afford an SSD make that the OS drive and use the 2TB for media storage.
Yes, that would work.
RAID 0 just distributes data across the two disks. Striping two 200GBs, regardless of their speed, would give you 400GB of storage and faster read/writes.
Cheers for that, I get it now. I think instead of trying to figure out why you get faster read/write times I'll just acknowledge that, as with many technological things, it happens and I don't know why.
When I finally come round to building this thing I will make sure to acknowledge the help I've received on here from various people. May be a long post.
AaronWHUFC
22-01-10, 21:29
You get faster read/write times because the speeds of the drives are combined!
But you rarely get the speed of both drives added together, so 100% of the theoretical speed. Don't ask me why, I have no idea!:o
So surely then it can still be of benefit? Even if you aren't going to get the speeds added together, even to get 25% of what you could get could be a significant speed increase.
AaronWHUFC
22-01-10, 21:43
So surely then it can still be of benefit? Even if you aren't going to get the speeds added together, even to get 25% of what you could get could be a significant speed increase.
Two drives = Twice the failure rate
If one drive breaks, the other wont hold windows. The other would need a format/clean install.
Also, the issue about size, where the lowest drive capacity is the same for both.
I set up a RAID-0 for the first time recently.
It's very easy to do, just get 2 identical HDDs and set up a RAID-0 for your windows installation. If you move to 2x SSD's you will definately notice the difference. :)
wonderlust
23-01-10, 15:43
but remember that if one disk or the array fails you WILL loose all the data stored on the disks.
Raid 0 is fine for OS only, but make sure all the user profiles on that machine are migrated to a different disk.
best way i can desscribe it is like dual channle ram but for your hdds, it speeds up because you have the ability to move twice as much data thru the 2 cables at once. now that is only the theorical speeds and not what you will get in truth but you do get a big boost.
im all for raid 0 or striping drives as its a very cheap way of getting great performance from the slowest part of your pc and have been using it for a few years. yes there are dangers as mentioned because all the data is split across the drives in the array so if you lose a drive you lose al the data but you can set it up, if you have a 3rd drive (or more depending upon how many you have your array) just for data, so all the important is safe. well its safe if that disk isnt the one that fails.
imo the only way to keep data safe is to burn it to disk and keep them safe as any hdd can fail, and if you run an array and oc chances are you will bugger it up once in a while when you try for those last few mhz. i lost all the pictures from when my daughter was first born and trust me that didnt go down well but you live an learn.
DayGloScooter
31-01-10, 22:29
I have had so many problems with RAID. Striping is prone to failure, whilst mirroring is no better than a good backup, and if something gets corrupted, so does the mirror, often enough. RAID 5 needs a dedicated card to make it work well.
The big problems are upgrading, where you need to change multiple disks instead of just buying one new one, and power draw, 5 x 500GB in RAID 5 draws much more than a single 2TB and is no faster really.
It's all just a big disappointment. Spend the money on fast disks / SSD's and a decent backup arrangement.
I have had so many problems with RAID. Striping is prone to failure, whilst mirroring is no better than a good backup, and if something gets corrupted, so does the mirror, often enough. RAID 5 needs a dedicated card to make it work well.
The big problems are upgrading, where you need to change multiple disks instead of just buying one new one, and power draw, 5 x 500GB in RAID 5 draws much more than a single 2TB and is no faster really.
It's all just a big disappointment. Spend the money on fast disks / SSD's and a decent backup arrangement.
After looking at benchmarks and the advice here I have decided to get a 1TB F3. Then when I can afford it, another, but not to RAID. I will store everything on these for now including OS. Then when I can afford it, an SSD as the system disk, with media files on the 2 F3s. Does this sound sensible? As far as I could see they were among the fastest 1TB drives.
its the safe and sensible option yea m8 :)
DayGloScooter
01-02-10, 18:14
its the safe and sensible option yea m8 :)
Yep, wish I'd done that on day one.
northturton
03-02-10, 08:02
If you can afford the disk space, RAID is a good idea, but don't forget to make backups (DVD?) and verify.
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