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rohit
03-24-05, 02:11 PM
what is RAID in brief.?
now that i ve got 2 HDD's can i raid them?
Any performance improvements with raid.?
Risks?

should i RAID these two? 1]120GB Seagate SATA (7200)
2] 80GB SAMSUNG PATA (7200)

How in order to maximise performance with minimum risks.

FastM
03-24-05, 02:20 PM
1st, When going to setup Raid both drives have to be indentical make/model....

So no you cant use the 2 your suggesting

2nd, Some people argue about this but i have always noticed huge performance increases when using Raid-0 (stripping), from general windows stuff to loading times in games.

3rd, When using raid, each file copied is split with each half going on either drive... so if 1 of your 2 drives in the array failes, all your data is lost. To me thats means nothing though, even if i wasn't running raid i would still always have an up-to date backup system.

Daneel Olivaw
03-24-05, 02:27 PM
Well, that's half true. You could raid different sized disks (I did, 80GB and 82GB), but you loose the surplus on the bigger. Your 120 + 80 would become 80+80 with no way to use the leftover space.

There is a performance increase, especially in everything sequential, formatting for example is about3 to 4 times faster (I have no clue why it's not twice), moving larges files is close to 50% faster. I mean large files.

Btw we're talking raid0 here.

But I have lost all data on my array 4 times in 2 months because of a faulty sector on one HD. Now I don't use the raid no more. Fast is fast enough.

edit: Oh dear god, you CANNOT raid a parrallel HD with a SATA HD. Unless maybe you put em both on a parallel raid controller with a Sata to Pata adapter...

Seriously, don't.

And btw, the maximum performance with minimum risk is no RAID at all (well, no RAID0). Ever.

Strahd
03-24-05, 02:37 PM
The slowest part of any PC is the read/write heads on a hard drive. I use Raid 0 because all the hard drive activity (in my case) is split between 3 hard drives. My load times are very quick.

I would recommend to anyone to use Raid 0 for disk drive performance. I would also recommend doing what I do is buy Ghost 9.0 ( or equivalent ) and a USB external hard drive to save your files and your partition.

If one of your Raid 0 hard drives fails, then all of your data is definetly lost. But a good backup/image of your system ensures you don't lose anything but some cash to replace the drive and some time to restore your last saved image :)

ricercar
03-24-05, 03:06 PM
There are two basic types of RAID. Mirroring and striping.

Mirroring (RAID1)creates one volume across multiple physical drives, with the disk capacity being the size of the smallest physical drive. The same content is stored on all disks with identical formatting. Each contains a complete copy of your data, so failure recovery is simple.

Striping (RAID0) creates one volume across multiple physical drives with the disk capacity being the size of all physical drives added together. The purpose of this is to speed access to the RAID, because the computer can effectively access more disk sectors at once.

You can create a RAID with a software RAID program or a hardware RAID controller. I've had significantly better success and dependability with a hwrdware controller, and would never go back to a software RAID program.

Rohit, one cannot maximize capacity and minimize risks at the same time. Fast access RAID0 doesn't include redundancy RAID1. (RAID comes in flavors from RAID0 through RAID5, with RAID10 being RAID1 plus RAID0 at the same time.)

RAID5 combines both, but is the most expensive. RAID 1+0 is perhaps the best compromise when money is conserved. RAID1+0 places the capacity of two volumes across four physical drives. Raid 5 places the capacity of three volumes across four physical drives, so the loss of one drive still allows complete recovery of data.

When the Western Digital 10K RPM Raptors were released about 2 years ago, many websites published research indicating that RAID0 did not help the average user with disk access speeds. Yet there are myriads of users who disagree..

SH64
03-24-05, 06:55 PM
Good info .. i was looking for info on RAID too :)

rohit
03-25-05, 03:13 AM
Thanx for all the info. I had some knowledge about stripping..but half knowledge is dangerous kowledge..
so now i am gonna give bak my 120GB Sata and sell of my 80GB PATA.

Ill get 2x 80GB Sata's + a DVD-RW. So that backing up essential data shouldnt be a problem. And do the RAID0 thing


(after a month or so. out of cash this month)

Kojiro
03-25-05, 08:49 PM
RAID is supose to mean Redundant Array of Inexpensive Devices, yet since you need more than one drive to use RAID, then it really isn't inexpensive alltogether. Maybe thats why I read in some books that RAID stands for Redundant Array of Independant Devices. Funny isn't it.

Yet there is no redundancy in Raid 0. Go fig

Here is my explanation of raid to those who are still scratchiing their heads

I think of Raid 0 as sort of like dual channel memory consept for hard drives (It makes it twice as fast) even though dual channel memmory came after raid 0. Dual Channeling 256MB DDR 400 dimms will give you 512MB space as RAID 0 of two 7200rpm 80GB Hard Drives will give you 160GB. Guess what both are going to be twice as fast.

Raid 1 is disk mirroring. Think of this as a carbon copy. Think of drive 1 as the paper you write on, and drive two is the carbon copy underneath it. If you loose the original one, you have the carbon copy. Since it's a copy, you loose space of the second drive.

Raid 5 is multi channel with parity, It can use the parity data to recover lost data. While having the full capacity and combined speed of all four drives (only 3 drives are needed for raid 5 to work) in a 4 drive array. The parity data can be written on any drive, thus when any one drive failes it can use the parity data on the other drives to restore it.

Raid 0+1 is what it is, Raid 0+Raid 1. This just one "dual channel" array being carbon copied by another "dual channel" array. for this reason Raid 0+1 needs 4 drives. RAID Controllers that support Raid 0+1 are cheaper than Raid 5 because they don't have to deal with parity data to rebuild the lost data. Everything is copied perfectly to the secondary array as if they were one drive.

There were raid 3 and 4, but these are obsolete and no longer used, so don't worry about them.