Quote Originally Posted by IanB View Post
I agree exactly with the reasons you have for the rant. But there are three reasons why someone (me for instance) would do exactly that...

The first is motherboard incompatabilities with certain disks. The particular bugbear I have in mind is the P5K Premium board, one that is still a killer except for the well-known problems with RAID and certain Samsung/WD disks, that are still not certainly fixed in later hardware/BIOS revisions for the board.

The second is the (related) ability to take the card + attached disk arrays and simply slot it into a brand new mainboard without having to worry about whether the Southbridge will read the disk arrays correctly. It likely will, between Intel ICH versions, but then what if you decide to switch to a SLI mainboard with an nForce chipset? Having a RAID card insulates you from that potential problem in upgrading, so it (and working disks/installation) can carry through many builds giving good value for the money spent.

The more expensive the card the better the future options too, you may not want or need RAID5 today, but a mix of RAID0 or RAID1 may do nicely, and then you have the power if you do wish to upgrade later and you aren't limited by the onboard Southbridge capabilities.

The third is the fact that if you are using SSDs or similar solutions, the Intel ICH has a bug that caps throughput and IIRC sometimes causes boot-up issues. Using an offboard hardware controller avoids the bandwidth cap even if for all other intents and purposes it operates no differently from the Southbridge RAID. Anyone with or intending to play with SSDs will therefore need an offboard controller even for RAID0 to make full use of the silly money they've spent. (Yeah, speaking as a 2x i-RAM owner...)

I think you also have to throw in the question of reliability too. The P5K Premium debacle shows that mainboards (perhaps from some manufacturers rather than others) are not terribly reliable and prone to manufacturing problems and design flaws, but also lack of commitment to fix bugs in "non-essential" areas of the BIOS or hardware, such as onboard RAID, which is basically added-on value to the board's main function. I don't know if there are any comparative reviews of the RMA rate or user satisfaction between RAID cards and mobos, but anecdotally on this forum you generally hear people swearing BY their Arecas and AT their Asuses...

The bottom line for this argument, it seems to me, is that RAID card manufacturers make a profit on their ability to make good hardware, and they compete intensively in a specialised market for this function only, so they have an incentive to get it right. Viz the recent Areca firmware fix for the X38 chipset problems with their cards, a little late but certainly welcome for their users. Mainboard manufacturers are just bundling an Intel add-on to their product, so it is not their PRIME focus of business and (as has been shown) their concern for its fitness has been dubious at best. Why are nVidia chipsets STILL destroying data on SATA drives? They can get away with that because people buy the chipset for SLI and know they can work around it. The specialised RAID hardware companies would die in months if they released a product like that.

So despite your unarguable technical objections, I respectfully submit there can still be very good reasons for preferring a RAID card over an onboard solution, in certain situations, however dumb the processing being done.
I have read your entire argument, and accept only one statement in it right now - that hardware controllers let you migrate to RAID-5/6. Please allow me to explain myself.

Concerning the first (P5K Premium compatibility issues) - issues with certain brands of hard drives? I'll want to see some proof of this, I've never heard of issues with different brands. I've never actually even heard of issues with it's on-board RAID offerings.

Concerning the second - I can do that with my software RAID card, at a fraction of the cost. I paid a high price (for this item) of $69.00 and have better RAID-1 and equal RAID-0 results to those who bought hardware cards (minus their cache, obviously), plus the ability to move my arrays as well.

Concerning the third - SSD's? C'mon, who owns one? Who can afford to? But OK, we'll look ahead into the future, by about 5 years. Frankly I'm not convinced any hardware cards out right now are really right for the speeds SSDs will have by the time we can afford them either. Sure they can decode RAID-5 off a regular disk just fine, but it has a lot of access time to do that in... with SSDs, that luxury is gone. If you want to do a lot of small file work on SSDs, you're getting a new card anyway.

Reliability? Nothing wrong with an add-on software RAID card. For that matter, I don't think there's a lot wrong with on-board RAID solutions, stability-wise anyway. But because we like to screw up our boards so much here, I'll concede those to you in this environment. I will not concede software RAID cards though.

So my bottom line is this:
My best practice for RAID1/0 would be to suggest an add-on SOFTWARE RAID card. It's still a piece of hardware you plug in, it just requires some software. Going to RAID-5? By all means, get the more expensive one. But if you're not, don't waste the money.

^ You'll note I did suggest the poster consider RAID-5 if he has the money for a card in my above post too...


Quote Originally Posted by [XC] itznfb View Post
software based RAID = fail
onboard RAID = fail

3Ware > Areca > Adaptec > Highpoint > Promise
Getting the same performance out of a $600 card that you could have gotten for free = Fail too.

Realizing that with my $70 software RAID I can take advantage of RAID-1 seek optimizations you can't with your $600 solution? Priceless.