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Areca 1882i Ver3.0 RAID 5 Read Speeds, normal or strange?

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Jeremiah Belt
Areca 1882i Ver3.0 RAID 5 Read Speeds, normal or strange?
on Sep 7, 2012 at 7:37:30 pm

I am almost done building my new workstation to replace my aging 2007 Mac Pro. The last piece of the puzzle is getting my RAID up and optimized. I have it up but I'm not sure if the numbers I am getting are normal or if something is wrong. It seems to have insanely good writes (cache helps) but the reads are not where I thought they would be by comparison. The read rate seems to slowly ramp up over a few seconds and then depending on which tool you use to measure seems to be fairly erratic, jumping from 3,200 MB's on one frame and the very next dropping to 467 MB's. Is this few second ramp up (between 2-4 seconds or over about 120 frames before leveling off according to the AJA tool) normal and why the erratic every other frame rate speed jumps? Is this going to adversely effect my color grading and editing? I mostly work 1080P 29.97 and 23.98 10bit uncompressed to ProRes/DNXHD, and do a lot of R3D grading and editing often exporting to 2K & 4K resolutions.

Here are the specs of my system and my raid. I also attached several images of the hard disk benchmarks highlighting the slow ramp up and the sporadic reads.

RAID Card:
Areca Arc1882i Vers 3.0 PCIE 3.0 6Gbs SAS/SATA Raid card (1GB cache)
-running in a full x16 PCIe3.0 slot. Both Physical and Electrical 16x. Blue slot.
8 internal WD Black Caviar 1GB, 7200rpm, 6gb SATA (all running same firmware)

System Specs: Window 7 64bit currently

Mobo: Asus Z9PE-D8 WS
CPUs: Dual Xeon E5-2687W's
GPUs: 3xGTX 680 4GB cards (all running at 16x in blue slots)
I/O: Blackmagic Decklink HD Extreme 3D (8x black slot)
HDs: 2xCorsair GT 240GB SSD boot drives and 1 WD Black Caviar 1GB for storage
1 Blue Ray Drive
PSU: Enermax MAXREVO 1350 watt

I did notice that if I disable the cache setting for "write back cache" the writes drop to about 180MBs but the reads do not have the ramp up and hit the expected 800MBs range quickly. So it's possible that this is normal with the cache of Areca cards or the specific benchmarking tools. As you can see by looking at the HD Tune readings, the read rates are not as erratic as the AJA tool describes...however the ramp up to start is still present.

I have tried setting up the raid without each disk in the series to try and see if it's a specific disk. Also every disk passes the WD multi-hour long Surface scans. I have also tried Aggressive read ahead, Every Buffer threshold percentage, Optimize AV settings, and the Read Performance Margin settings.

Any help thoughts or suggestions on what could be the issue and if there is really even an issue welcome. Would just like to get this squared away before closing up the case and committing the station to work.

<a href="http://images.creativecow.net/96053/benchmarks001a.jpg"><img src="//i1.creativecow.net/u/96053/benchmarks001a.jpg" border="0" /></a>
<a href="http://images.creativecow.net/96053/benchmarks002a.jpg"><img src="//i1.creativecow.net/u/96053/benchmarks002a.jpg" border="0" /></a>
<a href="http://images.creativecow.net/96053/benchmarks003a.jpg"><img src="//i1.creativecow.net/u/96053/benchmarks003a.jpg" border="0" /></a>


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Alex Gerulaitis
Re: Areca 1882i Ver3.0 RAID 5 Read Speeds, normal or strange?
on Sep 8, 2012 at 2:39:51 am

What RAID level is this, RAID0? (Sorry if I missed it in the post.)

I'd:
- check the cabling first, replace it
- reset the controller CMOS to defaults
- check the drives individually (bench each one, bench a couple in RAID0)
- try to get a replacement controller and see what happens.

From the look of it, cabling is the first suspect, the controller - number two.

Alex Gerulaitis
Systems Engineer
DV411 - Los Angeles, CA


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Alex Gerulaitis
Re: Areca 1882i Ver3.0 RAID 5 Read Speeds, normal or strange?
on Sep 12, 2012 at 7:25:55 pm

Apparently, a known issue with Areca 1882 series cards and RAID levels other than 0.

Alex Gerulaitis
Systems Engineer
DV411 - Los Angeles, CA


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Jeremiah Belt
Re: Areca 1882i Ver3.0 RAID 5 Read Speeds, normal or strange?
on Sep 12, 2012 at 8:42:20 pm

Thx Alex. Glad to know I'm not alone and it's possibly not other hardware issues. I'm running 8 6gb drives in RAID 5. I have noticed that the slow and sporadic reads are only shown in the AJA tool and Blackmnagic tools. The AJA tool shows huge variances of 3,000MBs on one frame and then 474MBs the next and right back to 3,000MBs the next. If you use HDTune or ATTO it shows much better and constant reads and only shows the slow couple second ramp up of the read speed. In HDTune with a 16GB file test it shows a fairly consistent Write of 882MBs and Read of 789MBs with that slow couple second ramp up below 500MBs at the top. Beginning to wonder if these new PCIE 3.0 cards are pushing a ton of bandwidth and are somehow not fully compatible with AJA and Blackmagics tools. I was able to playback 127 layers of 4.5K R3Ds with effects, transitions, and transfer modes in Premiere without batting an eye. Also tried uncompressed 4.5K and was able to do up to 10 layers before I gave up pushing it. I will try RAID 0 today. Keep me posted if you hear anything from Areca.


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Alex Gerulaitis
Re: Areca 1882i Ver3.0 RAID 5 Read Speeds, normal or strange?
on Sep 18, 2012 at 9:21:14 am

[Jeremiah Belt] " I was able to playback 127 layers of 4.5K R3Ds with effects, transitions, and transfer modes in Premiere without batting an eye. Also tried uncompressed 4.5K and was able to do up to 10 layers before I gave up pushing it."

Did you say 127? One hundred twenty seven? Holy Cow!

And ten layers of uncompressed 4.5K? 8-bit?

(Isn't that, like, over 200MB/s for a 4.5K 8-bit 4:2:2 stream? If so, this is a bit strange - 8 spinning drives shouldn't be able to get there even in RAID0.)

Alex Gerulaitis
Systems Engineer
DV411 - Los Angeles, CA


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Jeremiah Belt
Re: Areca 1882i Ver3.0 RAID 5 Read Speeds, normal or strange?
on Sep 18, 2012 at 6:44:06 am

Hey Alex. What are your thoughts on the ATTO ExpressSAS R608? I'm thinking of returning this Areca 1882i PCIE 3.0 and going with the ATTO card. This areca card has only been finiky and now the fan on it makes a fairly high pitch whine that is extremely distracting. Am I going to lose any performance switching over to this card? I'm currently getting 880MBs Writes and 787MBs Reads with 8 1TB WD 7200rpm 6Gb SATA drives. I'm on the fence. But the idea of a card with no fan intrigues me. As long as my system fans don't go crazy when the ATTO card is in like my Mac Pro does with it's ATTO R380.


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Alex Gerulaitis
Re: Areca 1882i Ver3.0 RAID 5 Read Speeds, normal or strange?
on Sep 18, 2012 at 9:14:57 am

ATTO got good products, has an eye on video / media applications (as well as enterprise) - so their R6 series controllers are my preferred alternative to Areca for now, as well. I've seen over 1GB/s reads on RAID5 on 8 drives, 1.6GB/s on 16 with ATTO R680.

They do get hot, so good airflow will help.

Alex Gerulaitis
Systems Engineer
DV411 - Los Angeles, CA


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