RAID or not RAID

[jexjex]

Hi
Thinking of buying two Raptors for use in video editing. Should I set up as RAID0 or both seperately?

Thanks

 

[RichPLS]

RAID 0 would probally benifit you.
Even more so would be a hardware RAID controller, verses your onboard RAID software mobo controller.


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[jammydodger]

Do you really need a hardware RAID controller for RAID0? Its not really CPU intensive?

 

[smitbret]

No, you don't. You'll still get a speed advantage with RAID 0 using the onboard chipset. For what it's worth, the onboard RAID is hardware, not software as you may have previously been led to believe. It just might take a couple of CPU cycles more to run than an independent RAID card.
-Brett

 

[jexjex]

Thanks for all your replies. Much appreciated.

 

[jammydodger]

You sure its hardware?

 

[smitbret]

If it's not hardware, then why do they refer to it as a chipset, i.e. Hight Point 374 chipset.
-Brett

 

[RichPLS]

There is no processor, The processing to manage stipes is the Pentium or Athlon.
I do not know of any hardware on-board SATA/PATA RAID solutions.
Some workstation dual proc boards have a SCSI add-in card for their onboard SCSI controllers which use hardware RAID.

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[smitbret]

I think we are confusing hardware RAID with software RAID. If there is a chipset on the motherboard, then it is hardware RAID. Yes, it may require the use of clock cycles from the CPU, but it is still hardware RAID. There is such a thing as software RAID, it has been available with the Dynamic disk setups since Windows 2000, but that is a far different beast. A RAID card will probably give better performance as long as it has it's own processor, but the onboard hardware RAID controller will function just fine.
-Brett

 

[jammydodger]

Then why are they advertising a SATA RAID 0+1 controller add in card as using software RAID? <A HREF="http://www.dabs.com/uk/channels/components/controllersandiocards/" target="_new">http://www.dabs.com/uk/channels/components/controllersandiocards/</A>

 

[RichPLS]

Hardware add-in RAID cards cost more than software add-in RAID cards, and much more so.
The difference is in the performance.
If you are performing video editing, a hardware RAID card will greatly improve your performance verses a software RAID solution.

_____________________________________________
<font color=red> And the sign says "You got to have a membership card to get inside" Huh
So I got me a pen and paper And I made up my own little sign </font color=red>

 

[jammydodger]

Yeh thats what I thought, but smitbret was trying to convince me that crappy add in cards use hardware RAID.

 

[smitbret]

So what then distinguishes something as being hardware versus software RAID?
-Brett

 

[jammydodger]

Hardware RAID when the RAID functions are handled by the card, software RAID is when the CPU handles the RAID and the card mearly provides an interface.

 

[smitbret]

So why would you even need the add in card, then? If it's just software, then couldn't you find a program that runs a RAID setup through your normal IDE or SATA ports?
-Brett

 

[jammydodger]

Windows 2000pro can provide RAID 0 and 1 though your PATA ports I think, linux can aswell. However you have to have the operating system installed to tell the processor how to split the data and then re-combine it. A software RAID card does the job of telling the processor what to do.

Or so I understand it, I could be wrong.

 

[smitbret]

I just looked a little more closely at the RAID card that he was thinking about purchasing. After reading the fine print, you are right, this card uses nothing more than software RAID. I was surprised, since I didn't think they even made anything like this, hence my insistance that it must be hardware, sorry. Seems like a ripoff to me. If he's on a budget and needs a true RAID card, he should check out www.highpoint-tech.com. These have worked great for me in the past.
-Brett

 

[scalar]

Yes, the big deal with software RAID-on-card is that the RAID array itself is bootable. A mirrored array can have either drive fail and the system can still boot from the good drive.

With windows or linux based mirrored RAID, the operating system itself sits on a third non-RAID drive. The idea here is that the OS and its applications are far less important than your server's data. You can lose the OS boot drive but still retain all your RAID-mirrored data. This may not make much sense if you are using striping or spanning/JBOD.

Software-RAID-on-card allows both the OS and the data together to sit on a directly bootable RAID mirror/stripe/span drive set.

 

[scalar]

You should use RAID to merge the drives because typically video editors have two sets of data to manage:
- your actual video clips
- pre/post-process temporary files

Both of these can be huge, and it can be messy to try and manage the size of one drive or the other so that the program doesn't run out of room for your movies or its temp files.

RAID makes many drives (up to seven or more with some RAID controllers) appear as one huge volume so there's no need to manage free space across multiple drives. The OS and editing program treat the drives as a single huge volume and your space management becomes very easy. Both your video clips and the temporary files just automatically spread across all drives in the RAID set.


If you have two identical-sized drives you will get a bit of a speed benefit by using striping rather than spanning/JBOD.

Striping shuffles data evenly across both drives in very small pieces or "stripes". If you need lots of data to move very quickly, striping overcomes the read/write delays of a single drive.


Drive Spanning or JBOD simply stacks the drive space like a stack of encyclopedias, and they don't need to all be the same size. Data is written to one drive until full, then then continues writing onto the next drive, and the next, and so forth. But since the 2nd drive is not even used until the first is full, your overall read/write throughput may be only about half the speed of striping.


Note that striping/spanning give NO data protection. If any one drive of the array fails you will very likely lose ALL the data in the stripe/span set.