Anyone explain RAID?

Level 0 -- Striped Disk Array without Fault Tolerance: Provides data striping (spreading out blocks of each file across multiple disk drives) but no redundancy. This improves performance but does not deliver fault tolerance. If one drive fails then all data in the array is lost.

Level 1 -- Mirroring and Duplexing: Provides disk mirroring. Level 1 provides twice the read transaction rate of single disks and the same write transaction rate as single disks.

Level 2 -- Error-Correcting Coding: Not a typical implementation and rarely used, Level 2 stripes data at the bit level rather than the block level.

Level 3 -- Bit-Interleaved Parity: Provides byte-level striping with a dedicated parity disk. Level 3, which cannot service simultaneous multiple requests, also is rarely used.

Level 4 -- Dedicated Parity Drive: A commonly used implementation of RAID, Level 4 provides block-level striping (like Level 0) with a parity disk. If a data disk fails, the parity data is used to create a replacement disk. A disadvantage to Level 4 is that the parity disk can create write bottlenecks.

Level 5 -- Block Interleaved Distributed Parity: Provides data striping at the byte level and also stripe error correction information. This results in excellent performance and good fault tolerance. Level 5 is one of the most popular implementations of RAID.

Level 6 -- Independent Data Disks with Double Parity: Provides block-level striping with parity data distributed across all disks.

Level 0+1 -- A Mirror of Stripes: Not one of the original RAID levels, two RAID 0 stripes are created, and a RAID 1 mirror is created over them. Used for both replicating and sharing data among disks.

Level 10 -- A Stripe of Mirrors: Not one of the original RAID levels, multiple RAID 1 mirrors are created, and a RAID 0 stripe is created over these.

Level 7 -- A trademark of Storage Computer Corporation that adds caching to Levels 3 or 4.

RAID S -- EMC Corporation's proprietary striped parity RAID system used in its Symmetrix storage systems.

IMO, RAID 0 is worth it for anyone who considers themselves a gamer. I have not done benchmarks and test and what not, but I have seen the effects of my current set up. Prior to adding raid 0 I had the following set up.

IC7-G Socket 478 Mobo
Prescott 3.0e
9800pro 128mb
512 mb RAM
Maxtor 250 gig SATA

After looking at my systems inability to keep up with load times and the constant lag I was getting in games I dropped 268 dollars on 2 gigs of Corsair-XMS RAM. This cut my lag time upon entering Ogrimmar in the World of Warcraft game down form 25 seconds to maybe 7 seconds. I then dropped 203 dollars on two 36gb Raptors, which I promptly put in a RAID 0 array. This has taken me from the 7 seconds of lag I had down to 0. I can now do anything in that game and not experience even a hiccup. For you guys who play WoW you will understand what I am saying here as now even Alterac Valley has no lag.

If I were someone considering RAID 0 I would absolutely get the 36gb Raptors, RAID 0 would make these approx 74 gigs total. The reason being is RAID 0 is not fault tolerant, so you wouldn't want massive amounts of downloaded information on these drives. Instead you put your games and O/s on here and get a larger, slower/cheaper drive, that will hold all your downloaded things.

RAID 0 can be a bear to set up if you don't have documentaion. My motherboard is not supported anymore but I was able to get a copy of the motherboard manual in *.PDF form off the intraweb. Unfortunatelly the manual didn't have much to say about RAID, just a few blurbs. After a little fumbling through the BIOS and a few bad driver downloads I had my RAID 0 up and running ( each bad driver download meant a new install of Windows for me as I only had the one machine I was installing RAID to). I could not be happier with the end product.

I currently have a Seagate Barracuda 7200.7 160GB @1.5Gb/s hard drive and I'm thinking about setting up a raid 0. My question is, do I have to get another 7200.7 @ 1.5Gb/s for the raid setup to work or can I get the newer 7200.9 @ 3.0Gb/s and still have it work properly?

Here's a question - if you have 4 hard drives, and want extra performance and redundancy, and can't do RAID 5...

a)Level 0+1 -- A Mirror of Stripes: Not one of the original RAID levels, two RAID 0 stripes are created, and a RAID 1 mirror is created over them. Used for both replicating and sharing data among disks.

b)Level 10 -- A Stripe of Mirrors: Not one of the original RAID levels, multiple RAID 1 mirrors are created, and a RAID 0 stripe is created over these.

Which would be best?

You can mix the two different disks. But both will operate at the speed of the slowest disk, of course. Also, both can be different sizes, but the size of the array will be 2 x the size of the smallest disk.

I have thought about it, and I think the best idea would be:

a)Level 0+1 -- A Mirror of Stripes: Not one of the original RAID levels, two RAID 0 stripes are created, and a RAID 1 mirror is created over them. Used for both replicating and sharing data among disks.

Agreed, I would choose option ( A: ) as well. Sorry for tardiness.

xp keeps rebooting with sata installed

Hi Guy's..... Need help with my computer, I have a 40gig ide hdd and a 80gig sata which connects via pci card. The 40 has win xp sp 2 on and the 80 is storage, I reformatted my 40 and pulled the sata out at the same time. Now I can not get my 80 to work again, the comp boots up to the xp flash screen and then reboots again. I pull the cable off the sata drive and it boots up fine. I could do with some help if there is any one out there.......Starting to go up the wall :bounce:

What is RAID? I know it has something to do with a second hard drive, and that it is on my motherboard.

What is Raid?

Raid 1 and Raid 5 installation

Hi,
I would appreciated if any one could explain step by step, how to install Raid 1 and Raid 5 on an IBM server ? I have a new IBM 346 xseries server with 2 x 73.4 GB SCSI and 3 x 140 GB Scsi Drives. There is one Raid controller 7k card to be installed. I would like to install Raid 1 on the two 73.4 Disks and Raid 5 on the three 140 GB disks. I intend to install Windows 2003 OS on the 73.4 Hard disks and Oracle database on 140 GB Disks. Starting from very begining can anyone explain how to proceed. After installing Raid 1 and RAid 5, how do I test whether the installations are correct. I have not installed RAIDs so far and it is new to me.

Joseph
lawrencej@hotmail.com

Hello all. This is my first (but hopefully not my last) post on this site. I just wanted to say, that although I am not the most experienced person on this subject, I have used RAID in the past, and in all honesty, it was nothing but trouble, especiellay when my system crashed, and I tried to format and reinstall the OS. I would recommend not doing it unless absolutely necessary.

I would like to ask 3 questions regarding raid 0+1:

1) Currently, I am running XP on a WD 60gb HDD 7200rpm. I bought a new WD 60gb HDD 7200rpm. Can i install raid 0+1 without reformatting the XP WD?

2) I also have a Seagate 150GB HDD for storage. If I install raid 0+1 on my two WD 20GB HDD 7200rpm can i run games, music and programs off my 150GD Seagate?

3) How do I install Raid 0+1?


Sys:
Asus Intel P4C800-E Deluxe
Intel Pentium 4 @ 3.0GHZ
Ndivia Geforce FX5200 128MB DDR
Kingmax 2x512MD SDRAM DDR 400

Sorry for the bump, but I have one Hitachi Deskstar 7K250 now, but when I just put an extra one in and format that, What is the default RAID setup? RAID 1? If so.. what is the advantage of putting it in RAID 0? Can I merge the two together aswell? To make 1 HD of 500GB with two of 250GB?

I don't think I understand what RAID is for yet. Somebody care to explain?

Did you read all the posts in this thread? There are many links to info to explain RAID in this thread.

Oh sorry, I will do that tomorrow. Thanks. Must've missed it 'cause I'm too tired right now.

Edit:

Ok, so I've read the entire thread. This article was most helpfull.

But if I setup 2 drives in RAID 0, If 1 fails.. both fail. But how does a drive fail? I have absolutely never crashed a HD and destroyed all of it's content. So I think it's pretty safe to buy an extra Hitachi Deskstar 7K250, since the prices are lower then ever. About 20 euro's less then what I bought my first one for. But I also need a RAID controller right? How are they configured? Software? Or do they have a switch on them?

What is a good RAID Controller? I didn't see a post saying anything about that.

Could not initialize storage

Hey i dont think this error has much to do with RAID but recently when i have been trying to download a patch for world ofwarcraft it says "Could not initialize storage. "You may not have permission to write to the destination path." Does anyone know how to fix this isssue? I have had the game for a while and this is the only time the error has come up. I tried rebooting my cpu, running symantec, spybot, and giving myself administrator but this error stilloccurs.

OK, I've read the whole thread and many of the linked articles as well as links from those articles. I now have a decent grasp on the basics of RAID. What I have yet to see anywhere is how it's significantly better than just using multiple drives and storing different things on different drives. Why not use a smaller drive to boot and run the basic desktop apps, then use other big drives as dedicated storage for various intensive programs? Seems this would provide the same benefits as RAID with a lot fewer hassles.

For example, I could run my desktop with all it's crappy little games and stuff off a 30-50GB drive, then have a dedicated 750GB drive for storing files for my 3D animation program, another 150GB drive for music, maybe another 300GB for photos. Wouldn't that be simpler? The smaller drives could be easily backed up on CDs which would only need updated when you changed the HD contents.

Raid 0 is supposed to give you a performance boost. You are reading from more than one drive at a time and data retrieval is faster. As you noted though if one of the two drives in the set dies all data is lost. Hard drives don't last forever and will eventually fail. Actually all you need is for windows to blue screen on you and you could loose the whole array and have to rebuild it.

I tried running Raid 0 for a while and didn't notice any great increase in speed. After rebuilding the array a couple of times due to windows glitches the novelty wore off. I just store things on different drives like you mentioned.