IDE RAID 0: killing multitasking! (long)

[otheos]

IDE Raid is not bad (Raid 0) for performace but it really kills multitasking. if IDE has a disadvantage again SCSI in mutlitasking, wait untill you see IDE RAID. It's hoplessly slow!!

IDE RAID 0 is good for A/V editing where sequencial read write matters.
Put the OS on it and you're dead. If you think of it, all the fuss about how multiple drives are beneficiary to performance is cancelled by IDE RAID 0 since you end up with one big disk where all heads are sync. Desperate.

I know Sandra lovers will be excited with the benchmarks but try moving a big file around in the array. I've done tried it:

it takes longer to move/copy a file from one partition of the array to another than to copy/move the same file between the two disks if they are seperate. It makes sence. It's the same as having one disk and two disks. No matter if the one disk is almost 2x faster than the two appart.

Try this. Put the OS on the array and in startup put 10 programs.

do the same on the two disks apart with the OS on the first disk and the programs on the other. Guess what? the array is slower.

Now after all this testing I still use RAID 0 with my two old UDMA33 10GB Fujitsus and I have to admit the loss is not great considering that each drive is now hopelessly slow.

Tried it on two GXP's and all my testing proved that unless you use RAID 0 for what it was designed, you actually lose performance compared to having the two GXPs seperately. i.e Put the OS and program files and you just killed it.

I know I'll take some heat from RAID0 lovers, but go ahead and do some weekend testing and see if I am right or wrong.

[NDC]

From my past experience multi-tasking on SCSI and RAID systems, I have also found that SCSI performs much better. I think it has a lot to do with the fact that SCSI disks support tagged command queueing (TCQ) which means it can execute multiple requests at the same time and would cause less pause
between requests...

Cadd: you should get a RAID 5 controller and use that instead rather than 0+1.

No, the performance does not "kill multitasking." I have 2 20GB drives in a RAID 0 and it's quite a bit more snappy than my 45GB drive... doing anything. Sure, if you compare it to a SCSI drive RAID, it's going to get creamed, but that isn't the point.

For price+performance, IDE RAID does an excellent job. The really good controllers all keep each drive on seperate channels where it really acts more like SCSI (to the computer) than not. In fact, many IDE RAID boxes are now shipping where they connect to the computer through a U2W or Ultra160 interface

[otheos]

With todays IDE hard drive's performace I'd recomend an IDE hard drive over a SCSI for singe user desktops anytime. Why? the cost! The SCSI is better but the price difference is not justified on a single user dekstop.

If someone else is paying for your system, SCSI is first choise as I always recomend SCSI CD/R/W/DVD devices over ATAPI. For the extra price of a little SCSI card you get a much more robust CD platform.

With the low prices of IDE drives 2 60GB drives that can do 8.5ms and ~40MB/s will do over 1 18GB Ultra160 + card. and you get 120GB over 18GB (WOOOAAA!).

As for RAID 0, try it yourself. But I insist if it's not used for what it was designed for, it;s only good when used to revive a couple of old(er) drives (again not as primary drives).

The bus is going to be limited more by the card than by the type of RAID. I really have no idea which RAID card could handle a higher PCI clock than normal (I have my promise card just a couple of PCI MHz over spec and it runs ok).

If all you really want is blinding performance, I believe some cards/setups can support up to a 4 drive RAID 0. I'd still recommend RAID 5 since the more drives you add, the greater chance you have that one will die (and in a RAID 0, that means you'll lose all data), but I do believe it's doable.