1 big HD or 2 small HD...??

[tuando]

Hi,

I will put up a system from the ground up anytime soon and start to gather much information as I can.
Is it better to have one big 45G HD (IBM DESKTAR 75GXP) or 2x 20GB HD (IBM DESKTAR 75GXP & MAXTOR DIAMOND MAX + 45) in the same channel Pri master & slave? What is the main advantage of setting up a RAID? What do I need in order to set up a RAID? Any explanation is greatly appreciated.

[qball]

First RAID is Random Array of Inexpensive Disks. The concept is to used multiple disks to store data, so if one disk fails, there is some redundancy and recovery options. There are various levels of RAID;

RAID-0. This technique has striping but no redundancy of data. It offers the best performance but no fault-tolerance.
RAID-1. This type is also known as disk mirroring and consists of at least two drives that duplicate the storage of data. There is no striping. Read performance is improved since either disk can be read at the same time. Write performance is the same as for single disk storage. RAID-1 provides the best performance and the best fault-tolerance in a multi-user system.
RAID-2. This type uses striping across disks with some disks storing error checking and correcting (ECC) information. It has no advantage over RAID-3.
RAID-3. This type uses striping and dedicates one drive to storing parity information. The embedded error checking (ECC) information is used to detect errors. Data recovery is accomplished by calculating the exclusive OR (XOR) of the information recorded on the other drives. Since an I/O operation addresses all drives at the same time, RAID-3 cannot overlap I/O. For this reason, RAID-3 is best for single-user systems with long record applications.
RAID-4. This type uses large stripes, which means you can read records from any single drive. This allows you to take advantage of overlapped I/O for read operations. Since all write operations have to update the parity drive, no I/O overlapping is possible. RAID-4 offers no advantage over RAID-5.
RAID-5. This type includes a rotating parity array, thus addressing the write limitation in RAID-4. Thus, all read and write operations can be overlapped. RAID-5 stores parity information but not redundant data (but parity information can be used to reconstruct data). RAID-5 requires at least three and usually five disks for the array. It's best for multi-user systems in which performance is not critical or which do few write operations.
RAID-6. This type is similar to RAID-5 but includes a second parity scheme that is distributed across different drives and thus offers extremely high fault- and drive-failure tolerance. There are few or no commercial examples currently.
RAID-7. This type includes a real-time embedded operating system as a controller, caching via a high-speed bus, and other characteristics of a stand-alone computer. One vendor offers this system.
RAID-10. This type offers an array of stripes in which each stripe is a RAID-1 array of drives. This offers higher performance than RAID-1 but at much higher cost.
RAID-53. This type offers an array of stripes in which each stripe is a RAID-3 array of disks. This offers higher performance than RAID-3 but at much higher cost.


First you need multiple disks and a RAID controller. Anyway, you set up your array to basically mirror or stripe your drives. Mirror is an exact copy and striping is storing the data across multiple drives. Actually, I am hardly an expert so check out ask.com or something and search on RAID.

As far as two drives better than one.... There is no advantage with two HDs on the same channel, as they each can only be accessed one at a time. If they exist on different channels, they both could be read/written at the same time. Two drive use twice as much power, take up twice the space, and could use a channel some other device could potentially use. Two drives offer more flexibility as if one fails, the other could still be used (assuming it is the one with the OS). One drive can be partitioned to appear as 2 drives. If one drive fails your SOL. One drive uses half the power and half the space.

The choice is up to you and the needs of how you will use the box.

Good luck.

[johnl_006]

Get 2 maxtor 30 gig hard drives. That's what I have and they are very reliable and when installed ans stuff will give you 28 gig!

[chipbgt]

.......what they said http://sysopt.earthweb.com/forum/smile.gif

Better to have two smaller in case one blows up on you.

[KAknight]

Get two smaller ones. Remember, its not IF a hard drive will die, its WHEN it will die.

[M_Six]

qball is right about RAID configs. To get true RAID, you need a RAID controller. This is called Hardware RAID. In Win NT 4.0 and Win2k, you can still get RAID 0 or 1 by creating either a mirror or stripe set using Disk Adminstrator. This is called Software RAID. It's not as reliable as Hardware RAID because if one disk gets hosed, you need a boot recovery disk to get in to the OS and break the mirror so you can boot from the other disk. With hardware RAID, the bad disk would be offline and the OS would still boot from the good disk.

The other down side of software RAID is that you can't create a complete stripe set utilizing all space on both drives. This is because you have to install the OS before you can get to Disk Adminstrator, so the space taken up by the OS is unavailable to the stripe set. Any remaining space on either disk can be used. You'd end up with a boot partition and a stripe set comprising all remaining space on both disks.

The least expensive IDE RAID controller I know of is made by Promise Technology at www.promise.com (http://www.promise.com) . It is hardware RAID and works very well, especially with Ultra ATA66 drives.

[Stan]

Hi,

Yep, go for 2 "smaller" HD instead of one big HD.
Forget about Maxtor and choose any IBM 75Gxp (http://www.storage.ibm.com/hardsoft/diskdrdl/prod/ds75gxp40gv.htm). They are simply the best !

More info about RAID can be found here (http://www.acnc.com/raid.html).

Depending on what you want to do with your PC, it is up to you to choose what level of RAID you want to implement.
At home I have 2 PC with the FastTrak controller.
My Gaming Machine has 4 IBM 22Gxp in RAID0. I don't need fault tolerance, I just want speed, speed and more speed.
My Server has 2 IBM 22Gxp in RAID1. As it is a file server, I need redundancy in case of HD failure (I also have a tape drive for full backup).

Now, if you have money, you can buy the new SuperTrak controller from Promise (RAID 0,1 and 5) with on-board memory (up to 128MB EDO RAM).

Stan

[This message has been edited by Stan (edited 08-03-2000).]

[Stan]

One thing...
It does not matter how many HD he is using if he implements RAID0.
If one HD goes down, all the data is lost. There is no redundancy in RAID0...

Stan

[tuando]

Thanks to everyone, your explanation is much appreciated. Especially qball who has spent time to explain RAID0-RAID53. Fortunately, there is a break between RAID-7 and RAID-53 otherwise I would really feel uncomfortable.

[lec169]

If you are building a system for home use and not too critical, Get 2 WDC's 30g's each for about $140us each. Then get a copy of Ghost. Part out the drives and use ghost to back up your critical partions on the second drive. every now and then, update the partitions. Just my $.02 worth. That way if you have to reload the system, you can in less than 15 minutes and you can change the setup.

[qball]

My defining work on RAID 2000 (RAID 2K), has been supplanted by the necessity to finish JAVA Chick 2.01.

lol.

[Alex31]

I thought Raid only went to 50
10 being One and Zero
20 being Two and Zero
30 being Three and Zero
40 being Four and Zero
50 being Five and Zero
Combining Five and Three has two differnet ways of writing to the hard drive for error correction

Please feel free to yell at me if i am wrong

[Tekkitan]

I think, i would have a 18gb SCSI drive for boot and programs, then a IBM 45gb or 75gb for storage purposes. I hear having an SCSI drive for booting and multitasking is GREAT and FAST. http://sysopt.earthweb.com/forum/smile.gif

[tuando]

I forgot one important aspect. I am thinking of backing up my entire dual boot partition (WIN2K and WIN ME totalling 8GB) frequently. Which option (1 BIG HD with multiple partition or 2 small one in a seperate channel W/ RAID) has the optimum performance (speed)?

[rogerf777]

I have a variation. For me the data is the only thing that matters.

I use a Promise FastTrak 66 controller with 2 Maxtor 20GB drives in Raid 1 Mirror mode.

I have also installed an UDMA/66 mobile dock in a 5 1/2" bay. I use DriveImage 3.0 to image my system daily to plugin drives in the mobile bay and rotate one of them off site daily.

Finally I use SecondCopy software from Centered Systems to backup key folders to a second machine on my network.

So far [knock on wood] so good ...