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Which type of RAID ?

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Anonymous
a b G Storage
November 10, 2001 7:03:58 PM

I have plan to build a intranet server(Win2k Server, Exchange 2000, MS SQL Server 2000, ColdFusion Server 5 with IIS 5 on it) with a raid support but I have some dillemas.

My plan is to have an onboard raid motherborard such as MSI Pro2-RU(KT266A) and double 100 GB 7200 rpm WD HDD for a Raid 1 installation. But I could not decide which type of raid is best for me. Raid 0 or 1 ? Or an onboard IDE raid solution is good enough to have it ? Or do you suggest an external raid controler such as Promise 100TX instead of onboard raid(it is also promise) solution ?

More about : type raid

November 10, 2001 7:43:46 PM

I would have to say I wouldn't do either 0 or 1. It really depends on how much this data is worth to you? I would get a real IDE RAID controller like the Adaptec ATA RAID 2400A. That way you can connect four drives to the controller and run level 5.

That way you can stripe data and parity over more then three hard drives. If one drive fails you can replace it and the array will rebuild.

<font color=red>1GHz AMD x MSI K7T-Turbo x 512MB PC133 x 2-Maxtor 30GB/RAID 0 = Stream Line Butterfly</font color=red>
Anonymous
a b G Storage
November 10, 2001 9:54:46 PM

You are right for general. But It is not a good idea to have 4 disk for a raid system. I have a daily backup system for my data. I think this is also enough for our job. It is not an enterprise level database. It will be a knowledge base system and one day lost does not affect too much our job.

I am trying to decide raid 0 or raid 1. If you ask me we do not need any raid system, but my boss "loves" raid system and he wants :( 
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November 12, 2001 3:49:44 AM

I would use Raid 10, aka 0+1. This gives you speed and redundency. Raid 3 and 5 are much slower.

Back to you Tom...
November 12, 2001 6:51:33 PM

Are you only going to be using two hard drives, or buying more? With only two, your only options are RAID 0 and 1.

<font color=orange>Quarter</font color=orange> <font color=blue>Pounder</font color=blue> <font color=orange>Inside</font color=orange>
November 12, 2001 8:22:49 PM

and 5 and 50

What's the frequency, Kenneth?
November 12, 2001 10:56:35 PM

Umm...since when can you use RAID 5 with only two drives? Did I miss something last week while I was in San Francisco?

<font color=orange>Quarter</font color=orange> <font color=blue>Pounder</font color=blue> <font color=orange>Inside</font color=orange>
November 13, 2001 12:21:01 AM

I can't understand why it requires three, but my manual says it does. Sorry.

What's the frequency, Kenneth?
November 13, 2001 3:35:13 PM

It's because of the way the parity is split up. I'll find a pic for you, just a sec...

<A HREF="http://www.techweb.com/encyclopedia/defineterm?term=rai..." target="_new">Scroll down a ways</A>

<font color=orange>Quarter</font color=orange> <font color=blue>Pounder</font color=blue> <font color=orange>Inside</font color=orange>
November 13, 2001 8:29:30 PM

Makes sense, but they COULD have done it with two drives if they had wanted to incorporate such a configuration in the specification. Anyway, I don't like the fact that they implied RAID3 is faster than RAID0, it can't be faster, and it almost always has to be slower, because it takes some time (no matter how small) to generate parity, and that extra parity bit uses up a portion of the bandwidth.

What's the frequency, Kenneth?
November 13, 2001 9:12:57 PM

I agree, I didn't find the speed references very accurate. But it has a great explanation of the different modes, at least.

<font color=orange>Quarter</font color=orange> <font color=blue>Pounder</font color=blue> <font color=orange>Inside</font color=orange>
Anonymous
a b G Storage
November 15, 2001 8:27:55 AM

Actually, you can RAID5 any number of drives (last time I did that I had three partition sets), as long as you can use one set to store the parity of the other sets (theoreticly speaking - what actually happens, of course, is that all sets are used to store the parity of all sets - or somesuch, it gets pretty technical from here on, so I'll stop ;-). you can even do RAID5 on two partitions (note - partitions, not drives : using the right software you can RAID between paritions on the same drive !), it just would probably be a waste of disk space and performance (a complete waste if space-time continuum if you wish ;-).
Anonymous
a b G Storage
November 15, 2001 8:41:29 AM

Oohh.. almost forgot :
It's really nice that MS has finally included a software RAID solution in their OS - pitty it (a) took them so long and (b) isn't up to par with the competition : on Linux you could do software RAID since 1994, and - more interestingly - you can do any kind of RAID you can think of, including 5, 10, 50 - whatever.
And another note : contrary to popular belief, any pariting RAID can be faster then (or at least as fast as) a simple stripping RAID : given the right setup. that means - making sure that storing the parity bit is always done in paralel with the actual data - all you need is very aggressive caching (which is provided on all free OSs) and the help of a nice SCSI adapter.

--
The light at the end of the tunnel is an oncoming dragon.
!