Stupid n00b RAID question...
Gadgetman53
Alabama, U.S.
So, my 74GB Raptor HD just came in earlier today. I ordered it to set up a RAID with an identical 74GB Raptor that I already have. I am hoping to decrease load times in games and what not, but I also want a set up that is stable. What is the best type of RAID setup for this? And do you have any tips on how I should do this?
MY SPECS:
ASUS P5GD1 Mobo.,
Intel P4 3.0GHz LGA775,
1 (now two) 74GB Raptors Programs and OS (the one I already have has an instal of windows should I format this first?),
1x 160 GB WD Caviar (storage),
2 Gig of Ram (4x 512MB in Dual channel),
ATI all in wonder radeon x600 pro vid card,
and a memorex dvd+- RW drive.
Any Suggestions would be helpful. I was going to have to reformat my drive anyway because of video driver problems so i decided to wait and set up a raid when I did this so that I wouldn't have to reformat twice.
Thanks in advance!!
Gadgetman53
MY SPECS:
ASUS P5GD1 Mobo.,
Intel P4 3.0GHz LGA775,
1 (now two) 74GB Raptors Programs and OS (the one I already have has an instal of windows should I format this first?),
1x 160 GB WD Caviar (storage),
2 Gig of Ram (4x 512MB in Dual channel),
ATI all in wonder radeon x600 pro vid card,
and a memorex dvd+- RW drive.
Any Suggestions would be helpful. I was going to have to reformat my drive anyway because of video driver problems so i decided to wait and set up a raid when I did this so that I wouldn't have to reformat twice.
Thanks in advance!!
Gadgetman53
0
Comments
Thanks
Now onto your thoughts. The common misconception is that running devices in RAID-0 (two drives acting as one with equal stripes) will significantly speed up your machine. Being realistic it won't improve it massively.
It's been long proven through countless articles around the web that RAID-0 without a dedicated hardware RAID controller only provides a small (eg.. 20%) performance increase. Now I am sure you currently wondering why...?
Although you have a RAID controller on your motherboard, the actual mathematical calculations to stripe/split the data onto the two disks is done by the PC not the controller. The controller is simply an interface into the system.
A dedicated RAID adapter has it's own processor and cache RAM installed that offloads the calculations and processing (along with additional dedicated memory for buffering operations) from your PCs processor.
At this point, I am sure you are starting to wonder if you wasted your money. You didn't. There are still benefits to be had, there is a performance increase if you RAID-0 them.
If you decide to mirror them(RAID-1), then writing performance is reduced from RAID-0 level (but about normal for single drive) with RAID-0 read performance. It's still better than a single drive
What would I do..? If you aren't storing anything on your system drive that you cannot afford to lose (as you have a data drive, it would appear you archive/store data you want to keep safe), then RAID-0 them for the most potential performance. You will see disk throughput performance increase quite respectably (especially as they are Raptors!)
Just remember that if you lose a disk in a RAID-0 (non redundant array), you lose everything on the other disk as well!
There is no such thing as a "Stupid" or "Stupid n00b (newbie or novice)" question on Short-Media. Regardless of how long we have all been around the computer industry, we are forever learning.
Knowledge about the world of computers has never been blessed upon anyone genetically (at birth). We all start from the same place - knowing absolutely nothing. Over time we progress from there.
Here on Short-Media, we share our knowledge and expertise freely. Providing support and advice for the newest novice up to the most experienced "experts". You will never be treated disrespectfully here because of your level of expertise or knowledge.
So! Welcome to Short-Media. Keep coming back.... and bring your friends! We are a friendly community here. :bigggrin:
The computer world has its own vocabulary which can be very confusing at times. If you remain around this industry, you will run across new words and terms all the time.
There are at least two terrific resources on the Internet to help you to wade through all those mysterious words and terms. Others may post more online references for you.
The first is called Wikipedia.org. It is an online encyclopedia and includes a great deal of computer and electronics industry vocabulary.
The second is Whatis.com It is an online dictionary whose focus is the computer and electronics industry.
You will find these and other online resources like it, invaluable.
Here is a definition of RAID from Whatis.com.
And here is a definition of RAID from Wikipedia.org.
Now where is my Java for Dummies book :O
Normally when you talk to a hard drive your controller it translates the requests and sends them to the hard drive's logic controller. pretty simple huh?
Well when in a RAID (Redundant Array of Inexpensive Disks) the RAID controller steps in and appears to the operating system to be the virtual controller and disk logic board on the drive. This allows the RAID controller to do many things differently.
RAID-0 : The controller takes 2,3,4 etc.... disks and stripes them together and presents them to the OS as a single disk with the appropriate drive geometry. Many people think this is spanning where you take 2 drives and write on the first until it overflows onto the next one. RAID-0 is not like this. Lets say you have a 128Kb file to write to a RAID-0. The RAID-0 has 2 drives and a 64KB stripe (a typical configuration). The OS transfers the file to tohe storage system as normal, but the controller grabs it. It sends a 64K data packet to drive 0 and a 64K data packet to drive 1. this speeds the operation because it doesn't have to wait between writes for acknowledgement from the drive that a data write has completed. The real advantage comes when it comes time to read the data back. It requests the stripes back from both drives at the same time so you virtually have the data transfer rate of both drives. It also almost eliminates mechanical drive latentcy (time it takes for the head to position and data to spin under the head). Problem with RAID-0 is no data protection. If one drive fails, all data from however many drives in the array is gone.
RAID-1: This is simply 2 drives that are mirrored to each other. The OS sees 1 drive. When controller receives a storage write, it writes it to drive 0 and then repeats it to drive 1. This means writes slow down as each write has to happen twice. Data reads however on a good controller are like a RAID-0 and both disks can be used for reading at the same time. In other words disk 0 gets file part1 and drive 1 gets file part2 at the same time. Data is totally redundant so if a drive fails you keep running on the good drive.
RAID-5: Requires at least 3 drives. Similiar to RAID-0 in the fact it is striped acrossed multiple drives. However parity has been added to the data. This means when the OS sends a file to the controller it writes the first data packet to drive 0, it then computes parity for the data packet and writes it to drive 1. It then writes data packet 2 to drive 1 and computes parity for the packet which it writes to drive 2, then writes next data packet to drive 2 and computes parity, writes that to drive 0. It just keeps rotating the data and parity writes in a circle. This is known as rotating parity. There are some RAID types which use fixed parity (dedicated parity drive), but they are not as common. Generally the RAID-5 suffers from bing very slow during writes since it has to also calculate parity and write it out too. Reads are usually fairly quick since it is a striped array allowing multiple drives to be used at the same time for reading. The whole operation slows down a lot when a drive fails since now the controller has to use the parity data to recreate the data from the dead drive on the fly. Only one bad drive is allowed. 2 drives failing loses all data from all drives. When you replace a failed drive, the contoller will start rebuilding the array by going out and reading the parity from all good drives and replacing the data on the new drive. A long and slow process though the controller does it in the background.
JBOD: Just a bunch of disks. Basically it is an option to use a single disk on a RAID controller. It basically has the controller make each drive a single drive RAID-0.
There is a lot more complexity involved with RAIDs than I put in here, but this is the basic operation of the 3 most common types. You'll hear about command queing, XORing, etc..., but that gets a little more in depth.
Hope it helps a bit.
Edit to my post..... "Everyone except Shorty, of course. A computer god if ever there was one!..."
Shorty I told you to keep your mouth shut, now everyone knows your secret...
MMMmmmm.... supper.... fooood... hungry....
I have a couple of questions for you re: RAID.
One is, I don't understand the 50% HDD capacity loss for RAID 1 for example. The contents is mirrored from HDD 0 to 1 . Is the data also redundant on each drive - hence the 50% HDD capacity loss?
Second, how does using RAID impact the types of HDD management utilities and processes one can use?
e.g., can one "image" or "partition" a RAID HDD as you would w/ a single HDD? Or must all HDD management take place w/in the RAID controller's user interface?
Exactly the same (except in one isolated case - Windows native RAID but that's a whole other subject)
The RAID is done at hardware BIOS level so the OS will only see a single drive which you can partition and configure as any other drive
What happens when it comes to restoring an image? Or is that a whole other can o' worms?
PS: Should I start another thread or should I stay in this one? Don't want to barge in on someone else's thread.
You can image a RAID array exactly the same as a single drive. Restore the same way.. there is only one minor caveat..
Your imaging software must be able to see the RAID controller. All RAID controllers because of their operation will require a driver of some description. That's in both Windows and in software booted off CD's such as imaging tools and Linux (as an example)
Most commercial imaging software (Ghost, Acronis etc...) can see RAID controllers without an issue but it's well worth checking with their hardware compatibility list first
Would the HCL be on (in this case) Acronis' site? Or somewhere else. I know Microsoft has an HCL data base but I thought that was a reference for hardware compatibility w/ their NT and above operating systems.
Once the RAID is established then you can do it.
Thanks for all the responses. I'm new to the whole RAID thing...
the first step to building the array would be to wook the drives up to the raid ports on the motherboard. next boot the machine and in the BIOS make sure that the raid function is turned on. when the machine is started it should show that the array is on and you cna hit ( insert key strokes here ) to enter the settings for the raid adapter. we'll go ahead and use F6 for the key strokes.
so when the machine is booting up and you see the computer's raid controler information come up and it says press F6 for setup or something like that you should then get to the raid controllers menu. this is how you identify what drives will be part of a RAID SET. so it will have a GUI that will let you scan for drives connected to the controller, then add them to a RAID SET and activate them.
next all you need to do is start installing windows as normal, BUT when it first kicks off the setup and at the bottom it says press F6 for additional raid and scsi drivers, you press F6, it continues to load normally then it gets to a promt where its asking for the drivers you want to add in to the installation of XP. use the motherboards device driver CD to browse to the drivers and continue, you might have to make a floppy disk with the drivers if the CD wont work in the installation of XP
The RAID controller will usually wipe all data from both drives when you set the array. Unless you are trying to recover a inadvertently damaged array you should always clear all data from drives when setting array. This allows the controller to write its "secret" RAID data onto the platter. It will usually either put it in the MBR or on the last track of the drive. It is always in a none accessible area.
Sooooo, if you've decided to start using RAID, you have to start your HDD build from scratch? Is it possible to install the RAID controller drivers while the system is still using a single HDD. Then image the single HDD. Next, set up the RAID controller w/ the array - let it whipe the HDDs. ...Then, restore the image - making sure that your imaging software supports the RAID controller???? Or am I totally out to lunch (my guess is it's the latter rather than the former.....
You may need to have a drive hooked up to the RAID controller in order for it to load the driver in WinXP. Some you do, some you don't. If you do, just hook up your second blank drive and set it to JBOD mode on the controller. After you have your image. Delete your JBOD array and set up your RAID-0 using both disks. Put your image back.
I have 8 drives in 4 arrays on my system. Each runs a diferent OS. I have 2 PATA drives and a USB2 drive as backup/secondary data drives. I turn my arrays on and off in the bios depending what I want to run. This sounds like a crazy setup, but I beta test a lot.
Don't worry too much about any size differences. The controller will automatically match size on all drives to smallest sized drive. A matched set of drives is always best, but when I was at Adaptec I built all kinds (1000's) of mixed drive arrays without a problem. A good controller should be able to handle almost any mix of brands and sizes. If the hardware and cables are good the array will work and be stable.
:woowoo: :woowoo: :woowoo: I think I'm getting a clue! - starting to grasp this whole RAID thang.
You've piqued my interest w/ your configuration. Sounds pretty sophisticated.
You're running multi-boot but each OS is on a seperate physical HDD?
And your data is on seperate physical drives as well, yes? (That's what I do, too. My data is completely isolated from my OS partitions (also on multi-boot systems.))
(an' where do you put all those drives?! that's a lotta drives even for a full tower. you must have some serious cooling and power going on....)
The 8 SATA drives are setup in 4 RAID-0 arrays of 2 drives each usually. Sometimes I do 4 drive arrays. Sometimes I even run dual level arrays of RAID 10 which is 2 RAID1's RAID0'd together. I just go into the bios and turn on Channel 1/2, or 3/4, 5/6, etc... depending on what I want to do. The worst thing is I leave all these drives spinning all the time. Even when their channels are not active. It's just the easiest way to reconfigure as I need to. Don't even have to take the side of the case off this way.
My apps and data are always on the swappable drives in the carrier. Backups reside on the NAS drives and a dedicated swappable carrier drive.
My CPU and Video cards are water cooled so Fans only have to pull drive, power supply, and chipset heat out of the case.
And before you ask ....... my power supply is a 750 watt so I can handle the power requirement.
I guess you could say I like to tinker a bit