onboard raid vs. dedicated pci raid controller

[BlahBlahYouToo]

how is an ICH10R compared to a Promise PCI SATA RAID adapter for example?

lets use RAID 1 since that is what i'm interested in, and the metrics i'm interested in is performance and robustness.

lets throw software raid into the mix as well (winXP).

 

[The Keeper]

Hardware RAID has better performance than software RAID. Dedicated RAID-controllers that are meant for workstations and servers usually are better than what are found on desktop PC motherboards. Actually I'm not sure if desktop PC RAID controllers even have built-in CPU or whether system CPU handles I/O. If they don't have one, then there's not much different to software RAID in terms of performance. On desktops, integrated RAID controller can be slightly better due to lower latency than optional controller (such as Promise) that sits on the PCI Express bus. But since the latencies are so low, there's minimal if any difference because HDDs themselves are bottlenecking.

Hardware RAID has a big downside however. RAID arrays created with one controller won't work on another. If you have a RAID array and your motherboard breaks, you need identical board with identical RAID controller if you want to keep your data. Careless handling of RAID arrays in those situations may result in data loss. I'm unsure if identical RAID controller on different brand or model motherboard would work. Wouldn't count of it anyhow.

Software RAID taxes system resources more but is more reliable as RAID arrays are not hardware-locked.

 

[BlahBlahYouToo]

so basically what you're saying is the ICH10R utilizes my main cpu to handle I/O so there will be a bigger hit than a dedicated raid controller.

and as far as robustness, if my mb dies, i'll need not only an identical onboard southbridge/raid controller, i need the exact same mb?

 

[The Keeper]

I'm not sure whether ICH10R has onboard cpu to handle I/O like dedicated controllers for workstations and servers do, probably not. Same with Promise controller. In which case I doubt there is noticeable performance difference compared to software RAID. However, any modern CPU should have little trouble handling I/O.

I can't be 100% sure whether a different motherboard with exact same RAID controller would work, but I've heard they don't due to vendor specific differences. Software RAID is probably about only choice if you want to be 100% certain you're not stuck with specific motherboard/controller. However, I'm not sure if you can switch from XP to 2003 or 2007 server and retain RAID array intact.

 

[RebateMonger]

Originally posted by: BlahBlahYouToo
lets throw software raid into the mix as well (winXP).

XP won't do software RAID 1 or RAID 5 (unless it's hacked).

 

[Jiggz]

IMO, if you want RAID 1 then you should go for a PCI RAID card. It gives you the flexibility to move the RAID setup to other mobo's if the need arises without re-creating or losing data. Just install the PCI RAID card to the new mobo with drivers and you're done. You need to research some reviews for a good PCI RAID card to make sure you get a fast and low CPU overhead (although with today's Duo's/Quad's CPU's, I/O cpu overhead is almost nothing). With mobo RAID's, you can still move the RAID setup when you switch mobo but it takes a lot of work. Back up the array in a bigger hdd. Delete the RAID array and build a new one on the new mobo and then restore from the back hdd's.

 

[JackMDS]

What exactly (in functional terms) you are expecting the RAID to do for you?

 

[specialk90]

I just had to join the forum to help you amid all this horrible information.

1) The ICH9R/10R southbridge chipsets work AMAZING for Raid. There are a few things you want when using Raid 1; one of those being able to read from both disks at the same time for the same file/data which speeds Reads up a little. Most cheap PCI raid cards cannot do this but Intel's can.
2) Intel's Matrix Raid allows you to create 2 different Raid arrays using one set of drives so you can create your Raid 1 for data protection and then create a Raid 0 if certain programs can take advantage of higher speeds. NO hardware Raid controller can do this.
3) The ONLY time you need a hardware Raid controller is if you wanted to use Raid 5 or 6. I won't get into the specifics of each but both require "Parity" data to be calculated for writes, which slows write speeds a little to a lot depending on how good the XOR cpu is. You won't be using Raid 5 so no need for hardware controller.
4) I have tested my ICH8R vs my $600 3ware hardware raid controller(PCI-E x4) using 4 150GB Raptors in Raid 0 and Raid 10 and the ICH8R was a little faster.
5) Last but not least, if the motherboard dies using Intel's ICH*R for Raid, it is as simple as getting another Intel board as current as the original or newer. If my board died with ICH8R, I can use the ICH8/9 or 10R chipsets. Now, since you are using Raid 1, there is no need to even remotely worry about that. Unless, of course, you add a Raid 0 array. Research Intel Matrix Raid.

 

[Paperdoc]

I have a mobo with Nvidia chipset that includes RAID capability. Last time I checked on their website, Nvidia claimed that ALL of their recent chipsets implement RAID the same, with the result that you can move HDD sets from one mobo to another as ling as they have Nvidia chipsets, and it will still work. Check their website for more recent info. Specialtalk90 implies that Intel does something similar. So although each chpset maker might lock you into their family, at least you don't have to worry about finding an exact mobo match.

That said, I'd treat that as a last-resort kind of insurance. If I were migrating all my data from a RAID1 array in one machine to a new one, I would much prefer to have a full backup before starting - and one that is verified to be sure you can restore from it BEFORE you start your migration.

 

[Paperdoc]

I have a mobo with Nvidia chipset that includes RAID capability. Last time I checked on their website, Nvidia claimed that ALL of their recent chipsets implement RAID the same, with the result that you can move HDD sets from one mobo to another as ling as they have Nvidia chipsets, and it will still work. Check their website for more recent info. Specialtalk90 implies that Intel does something similar. So although each chipset maker might lock you into their family, at least you don't have to worry about finding an exact mobo match.

That said, I'd treat that as a last-resort kind of insurance. If I were migrating all my data from a RAID1 array in one machine to a new one, I would much prefer to have a full backup before starting - and one that is verified to be sure you can restore from it BEFORE you start your migration.

 

[BlahBlahYouToo]

Originally posted by: JackMDS
What exactly (in functional terms) you are expecting the RAID to do for you?

mirroring, redundancy, i.e. RAID1

 

[BlahBlahYouToo]

Originally posted by: specialk90
I just had to join the forum to help you amid all this horrible information.

1) The ICH9R/10R southbridge chipsets work AMAZING for Raid. There are a few things you want when using Raid 1; one of those being able to read from both disks at the same time for the same file/data which speeds Reads up a little. Most cheap PCI raid cards cannot do this but Intel's can.
2) Intel's Matrix Raid allows you to create 2 different Raid arrays using one set of drives so you can create your Raid 1 for data protection and then create a Raid 0 if certain programs can take advantage of higher speeds. NO hardware Raid controller can do this.
3) The ONLY time you need a hardware Raid controller is if you wanted to use Raid 5 or 6. I won't get into the specifics of each but both require "Parity" data to be calculated for writes, which slows write speeds a little to a lot depending on how good the XOR cpu is. You won't be using Raid 5 so no need for hardware controller.
4) I have tested my ICH8R vs my $600 3ware hardware raid controller(PCI-E x4) using 4 150GB Raptors in Raid 0 and Raid 10 and the ICH8R was a little faster.
5) Last but not least, if the motherboard dies using Intel's ICH*R for Raid, it is as simple as getting another Intel board as current as the original or newer. If my board died with ICH8R, I can use the ICH8/9 or 10R chipsets. Now, since you are using Raid 1, there is no need to even remotely worry about that. Unless, of course, you add a Raid 0 array. Research Intel Matrix Raid.

good info, thx!
looks like i'll be going with a gigabyte ep45-ud3r.

 

[specialk90]

WAIT WAIT WAIT!!!

If you EVER want to add a PCI-Express Raid controller, then do not get Gigabyte boards. Their boards are not compatible with anything but the cheap 2port PCI-Express "x1" controllers. I have tried and I have read many times of people not being able to do it. The only 'success' story was someone using a cheap PCI-E x1 card in a x1 slot. Once you try their x4/8/16 slots, it is a no go. ASUS has worked flawlessly for me, FYI.

You are very welcome for the info.

 

[BlahBlahYouToo]

Originally posted by: specialk90
WAIT WAIT WAIT!!!

If you EVER want to add a PCI-Express Raid controller, then do not get Gigabyte boards. Their boards are not compatible with anything but the cheap 2port PCI-Express "x1" controllers. I have tried and I have read many times of people not being able to do it. The only 'success' story was someone using a cheap PCI-E x1 card in a x1 slot. Once you try their x4/8/16 slots, it is a no go. ASUS has worked flawlessly for me, FYI.

You are very welcome for the info.

i was gonna use the onboard sata raid (ICH10r).