Alex Gerulaitis
Forum Replies Created
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I was wrong about 8040. It’s the 4036 that ARC-1223 is not supposed to work with – at least not the SAS expander part – but you say it’s bundled? I’ll look into that.
A RAID controller isn’t required with 8040, just an HBA. 8040 supports SAS expansion (up to 122 drives via add-on boxes like 4036) – so that might be a good option if you need more than 8 drives in a RAID set.
[Neil Sadwelkar] “I didn’t get the dead end part with Thunderbolt.”
Can’t expand a RAID set beyond the number of drives in the box – at least not with Pegasus and Areca boxes.
[Neil Sadwelkar] “Or the 62.5% drop in efficiency with pass-through. What’s that exactly?”
Create a RAID6 set with a hot spare with eight drives. Two drives used for parity, one for a hot spare. That leaves five drives worth of usable space – or 5/8th space utilization efficiency (SUE) – or 62.5%. Create a similar set with 16 drives and your SUE goes up to 81.25%.
I.e. a maximum of 8 drives in a RAID set can be limiting in other ways besides capacity and performance.
Something tells me there will soon be TB2 arrays with built-in SAS expansion.
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Adding drives to an existing RAID0? Rebuild, most likely – but I’d consult Promise to be sure.
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ARC-1200 series don’t support SAS expansion, so no 8040 with that controller. 1800 series.
Other than that – it’s a personal choice. TB boxes are as “dead-end” as SAS non-expanders: with RAID6 and hot spare – 62.5% efficiency. If not worried about efficiency or flexibility (of, say, only array expansion and other niceties of decent RAID controllers) – then 8050 it is.
— Alex Gerulaitis | Systems Engineer | DV411 – Los Angeles, CA
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Amen to that, Bob.
There’s a limit what you can do with eight spindles in terms of speeds, and on top of it, Promise won’t put a $1K RAID brain into that box… or SSD caching… That said, we can probably rely on our friends at AnandTech to take it apart, put it back together and test it with eight decent SSDs… 🙂
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[Kevin Patrick] “Cost is not number 1 on my priority list. I’m willing to pay more if I’m getting more. Especially reliability. Even if it’s cerebral. At least in the price range I’m considering.”
All your points are well considered. Flexibility and efficiency (RAID6, hot spare, etc.), speed, capacity… R8 if the budget allows.
Go with the V10 Spyder Quattro variety if there’s budget for that. (Hahaha I am so funny.)
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[Richard Windsor] “I would like to start of with two WD enterprise class drives at 4TB a piece, will those work ok or is this list just a recommendation on this list?”
Nobody can guarantee anything until they either tested it, or bought an umbrella insurance policy, but it’s 99.99999% they’ll work. The list has decidedly consumer drives (e.g. ST4000DM000) on it – enterprise class drives should work.
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Thanks so much Peter!
Would it be possible to upload these to YouTube in all of their 4K glory? YouTube for a while limited uploads to 2K, but looks like 4K uploads are back now.
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Yes, love these. Glad you’re using good stuff.
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Never mind that – CNet review is bad, bad, bad. They don’t know what they’re doing. Pegasus is likely as fast as CineRAID.
You can also get the R4 even cheaper (or better): get it diskless for $700; 2TB WD Blacks or Se drives are around $150 ea; total – $1.3K. With WD Se drives, there’s also the benefit of “enterprise class”: allegedly better reliability vs. “consumer” drives used in G-RAID and Pegasus R4.
Hope this helps…
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Perhaps CNet reviews just weren’t done right.
Anandtech’s 2011 review of Pegasus R6 has some very respectable numbers: 674 and 684MB/s read/write when empty, slowing down to 423 and 463MB/s when full.
In RAID0 – almost 780MB/s. With SSDs – 1GB/s.
Pegasus2 R8 should only be faster.
CNet should re-do their testing… 😉
Also, this page (in Japanese) has videos and images showing Pegasus2 benching 800MB/s writes and 700MB/s reads.