RAID questions

[sig20paramedic]

Just some quick questions about RAID. First do your harddrives need to be the same speed(one drive is 5400 and the other is 7200). Second question is I think both drives are ATA100 but does is matter if one is ATA66 and one is ATA100??? Also is it better to use an addon card for a RAID setup or use what's on your motherboard(I'm building a new system and I was wondering RAID or no RAID when I buy the motherboard).

[Jeffbx]

You can mix speeds and even drive sizes if you want, but the array will perform to accomodate the smallest, slowest drive in your system. So, if you have a 5400RPM ATA66 & a 7200RPM ATA100, the array will only be as fast as the 5400.

On board vs. add on card really doesn't matter - that's more of a personal preference.

[Ladogaboy]

Here is a link to a thread with very good explanations of different RAID settings. There is a link to an article that should give you all the information you need.

[Markel]

Originally posted by Ladogaboy
Here is a link to a thread with very good explanations of different RAID settings. There is a link to an article that should give you all the information you need.
Link?

[Jeffbx]

This one perhpas?

http://www.acnc.com/raid.html

[sig20paramedic]

thanks for all the help

[sho.gun]

here's a previous thread that might shed some light:

http://www.gotapex.com/forums/showthread.php?threadid=34590&highlight=raid+questions

[assnips]

well what bout making ur ata/100 cards into a raid card..

i hear u can do it without soldering

[Ladogaboy]

Originally posted by Markel

Link?

Sorry, I must have canceled it on accident...

Here's the link:

http://www.gotapex.com/forums/showthread.php?s=&threadid=36748

[Heihachi]

Originally posted by Jeffbx
On board vs. add on card really doesn't matter - that's more of a personal preference.

Not sure I completely agree w/ you on that one.

Separate PCI raid controllers ARE faster than onboard.

[Ladogaboy]

Originally posted by chosenfool


that depends on the kind of ata100 controller they have. the promise fastrak66 is VERY easy (all it needs is one resistor grounded and soldered to a pin on the ROM chip - i have one and im actually using it now), but the fasttrak100 isnt as simple. im not sure about other ata100 cards (such as AMI or CMD), but id love to find a way to convert my ata100 CMD controller to a RAID card. especially if i dont have to solder anything (but i doubt that it would only be a matter of simply flashing the BIOS on the ROM chip - if there is such a way, and if anyone knows it, id like to know myself).

My question is why would you even try? There are several ATA100 RAID cards to be had for less than $30, so why would you buy a $15-20 ATA card, risk ruining it, and risk not getting the same performance for a $10 difference in price?

[assnips]

well what if u happen to trade with someone who throws in a ata/100 card but now u want raid...... it could happen :)

[Jeffbx]

Originally posted by Heihachi


Not sure I completely agree w/ you on that one.

Separate PCI raid controllers ARE faster than onboard.

Really? I always thought they were the same (given that it's the same card - I can understand if onboard is simple RAID & the add-in is some monster card w/128MB of cache RAM). Where are the benchmarks? I'd be interested in seeing the difference...

Thanx!

[Ladogaboy]

Originally posted by Jeffbx


Really? I always thought they were the same (given that it's the same card - I can understand if onboard is simple RAID & the add-in is some monster card w/128MB of cache RAM). Where are the benchmarks? I'd be interested in seeing the difference...

Thanx!

I think (I'm not quite positive on this) that the difference is that on board RAID uses software to do all the work, but RAID cards use hardware to do the work. It would be the equivalent of a software DVD decoder versus a hardware DVD decoder.

[Jeffbx]

Originally posted by Ladogaboy


I think (I'm not quite positive on this) that the difference is that on board RAID uses software to do all the work, but RAID cards use hardware to do the work. It would be the equivalent of a software DVD decoder versus a hardware DVD decoder.

No, that's the difference between hardware (RAID card) and software (OS controlled) RAID. Like if you set up a RAID0 system under W2K, you don't need a RAID card because the OS will handle the mirroring. This is definitely slower than a hardware solution where the card would handle it.

If anyone has stats that show the difference between an on-board SCSI and an add-in card I'd be interested to see it.

[Ladogaboy]

Originally posted by Jeffbx


No, that's the difference between hardware (RAID card) and software (OS controlled) RAID. Like if you set up a RAID0 system under W2K, you don't need a RAID card because the OS will handle the mirroring. This is definitely slower than a hardware solution where the card would handle it.


I know that, but I thought on board RAID controllers don't actually have the same hardware setup as RAID cards. I'm curious about this too, because I've always heard the cards are faster than onboard. This is one of the reasons why I haven't been looking at motherboards with onboard RAID.

[DREDD]

forget 10k RPM drives...go 15k RPM :-)

[DoPeY5007]

Originally posted by chosenfool

i would wet my pants if i ever get a 15K RAID0 setup... :laugh: :stupid:




ok my question..


I have RAID 0 witrh iWill ATA/100 side RADI card...


I am looking @ a dual PIII MB with on board RAID ( the promise chipset ) will that RAID be slower than the curent RAID I have :confused:

[DoPeY5007]

Originally posted by chosenfool

Not sure if its BIOS-flashable to support other arrays

I have a MB with onboard Promise ATA/66, to update the BIOS for the ATA/66 it has to be done by doing the MB BIOS upgrade, it is unable to be done on it own like a PCI card would be...



thanks that is what I though....

[Jeffbx]

Originally posted by chosenfool


one good thing about OS-controlled RAID is that bootup time is much faster (with a card its usually at least 10 seconds longer).

one not-so-good thing about i can think of is that it takes more resources from the OS, and can considerably slow performance of other programs.


One more drawback of OS RAID is that you can only have certain RAID levels (like RAID0) on the boot disk, because otherwise the OS couldn't read the drive before the OS is loaded. So you can't run a RAID5 array in software with the boot drive as part of the array.

[rajatQ2]

quick question, Raid0 and Raid0+1 would have the same data read time and throughput, but data write times and throughput would be slower on Raid0+1, right?