RAID questions

[blue&whiteman]

I want to buy a Sonnet Tempo ATA 133 PCI card and setup a RAID for performance sake. Here are my questions:

1. Which form of RAID is faster? Mirrored or Striped?

2. Will 2 identical drives give better performance? ie. same model, size etc.

3. Will I be able to boot from this RAID?

4. Is it good enough to setup this RAID from Apples disk utility?

Please feel free to add any important info I may have forgotten to ask about.

 

[LethalWolfe]

Unless you really need RAID I wouldn't do it. RAID 0 will give you a performance increase, but if either of the RAID'ed HDDs fail then you've lost all yer data.


Lethal

 

[blue&whiteman]

RAID setups are known to be much more reliable than single drives.

 

[hugemullens]

Raid 1 is much more reliable. Raid 0 is much less reliable. Raid 1 can actually hurt performance, Raid 0 helps. If you use apple's software Raid, no controller is nessacary. OS X would decied what goes to what drive. If you get a controller card OS X wouldn;t even know there is a raid. You must buy the same size, rotational speed and cache drives. The raid will be as slow and as small as the worst drive. You get a 40 and a 60 gig drive, the raid would either be 40 or 80 gigs depending on how you do it. If one is 5400 rpm then both will have 5400 rpm performance. Do some serious reasearch.

 

[legion]

Re: RAID questions

Originally posted by blue&whiteman
I want to buy a Sonnet Tempo ATA 133 PCI card and setup a RAID for performance sake. Here are my questions:

1. Which form of RAID is faster? Mirrored or Striped?

2. Will 2 identical drives give better performance? ie. same model, size etc.

3. Will I be able to boot from this RAID?

4. Is it good enough to setup this RAID from Apples disk utility?

Please feel free to add any important info I may have forgotten to ask about.

1. Striped, but there's more to it than just striped or mirrored (for instance there's striped and mirrored, parity, etc.) Also, just striped (RAID 0) offers no data protection (if one drive fails, both drives will have useless info on them)

2) The drives have to be of the same physical size. There is no option here. They can be different manufacturers, but remember your slowest drive will be the bottleneck.

3) You can boot from Apple's software RAID.

4) Yeah, I guess "good enough" Fact is software RAID is just a means to make a large logical drive. Hardware RAID (where you have a RAID controller card with a chip on board) will give you real performance. In this case, the card handles shuffling info about to the different drives instead of like in software RAID where the computer's processor has to take care of all of that.

I recommend that your boot drive is a small non-RAIDed drive. Though Apple allows you to boot off of its software RAIDs, it's not advisable. Also, don't bother partitioning RAIDed drives... there's no point (if you mull this about, I'm sure you'll figure out why.) RAIDed drives are best for storage. You should keep your OS, Applications on a separate drive non-RAIDed and any scratch disks (like for Photoshop, etc) on another separate drive (if you want best performance, one harddrive devoted to each applications' scratch disk) Then all your created content should be shuffled back and forth from the RAID.