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separate or raid 0 pro's & con's

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Ted Joyce
separate or raid 0 pro's & con's
on Feb 11, 2010 at 5:24:47 am

I am moving from one to two matched eSATA Raid5 4-drive disk arrays as I need more drive space. I am wondering what is the best way to use them?

Currently with just the one array for everything, I am fine for 2 tracks of audio & video and many edits from a few large source files. But I was having problems playing back as my projects got larger and more complex. I ended up with 3 video tracks from many short rendered video files, more than a dozen stereo audio tracks(sound effects, music, dialog etc.) in a long form project with lots of edits & color corrections. The timeline playback would stop at various places and tell me my drives are too slow. I had to render whole segments to complete the project.

I could use software to strip the two arrays as raid 0. I assume this would give me the most pure speed but would it increase the performance of the drives for many smaller reads from the many audio & video tracks much more than using the two drives separately?

Or I could use one array for source video, and the other for stills, audio, video renders etc. I like the simplicity of this approach & ease of drive trouble shooting, etc. I also suspect that it would offer improved random short reads for the audio tracks, possibly similar to the raid 0 as above. Of course it would not offer the large file read speed of raid 0.

Any advice would be greatly appreciated?



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Fred Connors Jr.
Re: separate or raid 0 pro's & con's
on Feb 16, 2010 at 3:28:55 pm

Hey Ted

The performance you are getting from your single RAID5 4-drive array is a little low. What is the brand and model of the raid controller?

If two matched eSATA Raid5 4-drive disk arrays are connected to an eSATA card with it's own RAID controller built in then you are all set. Some eSATA controllers are $55.00 and some are $200.00, usually the difference is the built in RAID controller.


If you use software to strip the two arrays as raid 0 with a simple 2 port card, you will not get the big bump in speed that you expect. A software RAID depends on the CUP to do the dirty work of splitting the data stream. This means a big performance hit and usually ends up in drive/subRAID corruption.


On the other hand a four port eSATA card with RAID and connect up to four Raid5 disk arrays for some very nice performance numbers.

Fred


The Troupe - Modern Media Design & Production


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Ted Joyce
Re: separate or raid 0 pro's & con's
on Feb 17, 2010 at 8:36:02 pm

Fred,

Thanks for reply. I am using a ADDONICS ADSA3GPX8-4E 4-port E-Sata PCI-E raid controller. I have 2 LaCie's 4Big Quadras & get about 132MB/s reads at NTSC DV25 frame size and 128MB file size out of the comb using AJA System Test.
The speed is higher with 720X486 10bit frame size and file size of 1GB, about 200MB/s reads. The drives clearly are not as fast with little reads.
My CPU on the Mac is an 2 X3.2Ghz Quad-Core. So striping or separate?
What software do you recommend for striping?

Thanks,
Ted



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Fred Connors Jr.
Re: separate or raid 0 pro's & con's
on Feb 19, 2010 at 5:23:02 pm

Ted

I do not have much experience with Addonics software, I know they have drivers for Macs but do they have Raid software/hardware for their cards?

If each of your Lacie Big 4 Quadras are setup as RAID 5 you could then configure the Host Card as a RAID 0 and have RAID 50.

You should see about 200 MB/s from each unit alone and about 360MB/s when stripped as a RAID50.

LaCie sells a card with bundled software that is tested with your drives.

http://www.lacie.com/us/products/product.htm?pid=11217

It looks a lot like this card for 1/2 the price and it appears to be a true hardware RAID on the card.
http://www.cwol.com/serial-ata/4-port-esata-pcie-x8-adapter.htm


Fred

The Troupe - Modern Media Design & Production


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Ted Joyce
Re: separate or raid 0 pro's & con's
on Feb 19, 2010 at 5:47:30 pm

Fred,
This has the same chip as the LaCie's card. I seem to remember them saying that I could just use the Mac's disk utility to strip the two arrays. Guess I should ck w/ them though.
Thanks,
Ted



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