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My motherboard, an Asus M4a79t Deluxe, advertises RAID 0/1/5 capabilities. My limited understanding is that onboard RAID is better than software RAID. Is this necessarily true? Is an onboard RAID controller closer in performance to a software controller or a dedicated hardware controller?
Mantas Vidutis
Posted 2010-04-16T19:53:52.070
Reputation: 301
26
Hardware RAID, which means buying a RAID card, and installing it in your computer is good.
Software RAID is low performance, but it's reasonably stable, and pretty reliable.
"Onboard" RAID, which is the crappy RAID emulation built into your motherboard, has low performance, AND low stability.
I have used onboard RAID before, and I have always regretted it. You gain nothing, zero, zip, from using built in RAID emulation, no matter how much you paid for the motherboard. There is no optimization, there is no performance increase. Lose a drive in a RAID 5...It can take literally DAYS to rebuild it. Likewise checking an array for errors, and errors WILL happen, because it's not reliable.
If you use software RAID emulation, at least you can put the drives in another machine and have a good shot for recovering the RAID. With an onboard RAID emulator? Impossible.
Satanicpuppy
Posted 2010-04-16T19:53:52.070
Reputation: 6 169
There is some on-board RAID that is hardware RAID, but if you've paid less than $400 or so for the motherboard, it's not hardware RAID. – Ignacio Vazquez-Abrams – 2010-04-17T02:06:57.390
4Agreed. If your options are fake RAID or software RAID, go with software RAID every time. – Matt Simmons – 2010-04-17T02:07:57.933
1Linux SoftRAID rocks meanwhile, so you're mistaken @ this point. – poige – 2011-07-21T15:55:37.807
There's also a number of RAID cards that are "fake-RAID" (most often the inexpensive cards). – afrazier – 2011-07-21T20:34:19.353
What you get from fakeraid is the ability to install and boot windows on the array, and also be able to access it in Linux. The performance difference between hardware and software raid is also almost zero except in extreme cases, such as a 12 disk raid-6, or a raid-10 using four high performance SSDs. If you are using only linux and no windows, then definitely go with software raid over fakeraid. – psusi – 2011-08-03T17:35:31.420
@psusi: The only thing I don't like about the windows software raid is that it doesn't mirror the boot sector, so if you lose the "main" drive, there is more maintenance than there would be for a hardware or a fake raid. I've never had trouble using software raids with linux, but I haven't really plumbed the depths of that since I usually have access to hardware raids. – Satanicpuppy – 2011-08-03T18:16:20.580
@Satanicpuppy eh? Last I saw, you can't install Windows on a software raid at all. You have to install it on a stand alone drive, then set up a software raid for data storage only. So it is a matter of the entire system drive isn't mirrored, not just the boot sector. Of course I quit using Windows after XP, so that might have changed... – psusi – 2011-08-03T18:20:06.793
@psusi: Huh. I'll admit to never having tried it until recently, but, in Windows 7 at least, it's pretty nice. http://www.softwaresecretweapons.com/jspwiki/windows-7-software-raid-disk-partition-and-volume-context-menus I actually like Windows 7 pretty well. It's a much more serious effort than Windows has put forth in the past.
– Satanicpuppy – 2011-08-03T19:30:25.6937
"they are perfectly adequate for someone that wants a simple backup plan"
Remember, RAID is not a backup strategy, it's designed to increase performance and or reliability of your storage!
Backup means getting the data synchronized off of the RAID array(s) onto another storage device.
Google for "raid is not backup" for countless articles that discuss the myth :-)
FlakRat
Posted 2010-04-16T19:53:52.070
Reputation: 71
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In my opinion, on board RAID is in fact a software RAID. Most of the job is done by dedicated drivers installed in the operating system.
Wacek
Posted 2010-04-16T19:53:52.070
Reputation: 363
1There are good RAID cards, but unless your willing to drop the scrilla ($), you are correct, poor RAID controllers offload most of the work to software. – None – 2010-04-16T21:41:38.850
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Depends on the RAID type. Been quite a while since I've seen benchmarks doing direct comparisons between pure software vs. on board, vs. dedicated, but from what I remember:
Like I said though, it's been a good 3 or 4 years since I've really read anything about the performance of on board controllers, and we've had 3 or 4 generations of chipsets come out since then.
Evan M.
Posted 2010-04-16T19:53:52.070
Reputation: 314
4It must have been awhile. Software-implemented RAID in Linux is on par with most other RAID in reliability and performance. Hardware RAID is preferred for other reasons. Using RAID onboard as in the motherboard-based RAID is a very bad idea unless you don't mind increasing the risk of losing your data. – Bart Silverstrim – 2010-04-16T22:15:22.977
Not only on Linux. Processors these days are really ast per core and have many cores - the overhead of RAID calculations is not even relevant in most cases anymore. – None – 2010-04-17T04:33:50.887
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As it's been said, motherboard RAID is usually about as good, if not worse, than hardware RAID. They are certainly not much faster. However, they are perfectly adequate for someone that wants a simple backup plan and doesn't care much about performance or crazy-level stability.
The only problem is that finding a good hardware RAID controller can be expensive. However, if you're data is that critical to you (or if you just want a FAST RAID 10 array), it's definitely worth the money.
Carlos Nunez
Posted 2010-04-16T19:53:52.070
Reputation: 173
1
The original proposition was "Onboard Raid VS Software Raid". As it has been said,"buying a RAID card, and installing it in your computer is good", better still buying a GOOD QUALITY Fast Raid card, SCSI or SATA, beats software or onboard in my experience. A myriad of setting determine the performance of your array, from picking the correct slot for the card,stripe size used,to Raid type, just to name a few. Spend the dollars on a good quality hardware option that's compatible with your system and you will not regret it. In my experience, our clients don't mind paying for Quality, we say to them, "How much is your downtime worth to you".
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I've made such good experience with software raid, that I'll never buy a hardware raid controller for private use. It's just not worth the money, since my bottle neck is the ethernet card with its 1gbit/s.
I'm using a 2GHz single core with 2GB RAM on a 5x1.5TB software RAID5 and there always comes the gigabit over the network (for a single user). bonnie++ says 160MB write and 250MB read (sequential).
Also my software RAID0 (on 4x500GB, 2G RAM, 2GHz dual core) delivers enough performance for our club's private use:
schmijos
Posted 2010-04-16T19:53:52.070
Reputation: 101
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Check this great thread out: http://serverfault.com/questions/214/raid-software-vs-hardware =)
– None – 2010-04-16T20:02:44.723but is the onboard controller that is in my motherboard considered hardware or software? – Mantas Vidutis – 2010-04-16T20:09:05.057
i find software raid to be more flexible, I've always run into problems with hardware raid systems. I once had a problem with bad memory on a raid card, no diagnostics could find it and it took the server out for more that a month while dell try to fix it. Oh dear. – None – 2010-04-16T20:14:24.500
all of these answers are useful, I will vote them all up if I get over 15 reputation – Mantas Vidutis – 2010-04-16T20:27:11.797
3The onboard controller on your motherboard is considered "fakeraid". I'd avoid using it for reasons outlined many times online and in Serverfault. – Bart Silverstrim – 2010-04-16T22:13:07.707