MP 1,1-5,1 Raid question

macguru9999

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Aug 9, 2006
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I was just wondering ..... A single samsung evo ssd in one of the 5,1 drive bays gives about 250mb/sec. If you use the osx raid utility to stripe drives in the bays, say 2 in 2 bays, or 3 in 3 bays , or 4 in all 4 bays , what are the speed improvements ?? I assume you dont get 2x 3x 4x the speed , but what do you get ? I imagine you are limited by the single? raid controller. I am using an ssd blade as a boot drive, but this raid would make one possible video editing option.
 

flygbuss

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Jul 22, 2018
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Stockholm, Sweden
I was just wondering ..... A single samsung evo ssd in one of the 5,1 drive bays gives about 250mb/sec. If you use the osx raid utility to stripe drives in the bays, say 2 in 2 bays, or 3 in 3 bays , or 4 in all 4 bays , what are the speed improvements ?? I assume you dont get 2x 3x 4x the speed , but what do you get ? I imagine you are limited by the single? raid controller. I am using an ssd blade as a boot drive, but this raid would make one possible video editing option.
Samsung 840 Evo in Bay 2 and Bay 3, Raid 0, chunk size 128K: 400-500 MB/s R/W
Adding a third drive doesn't improve speed as much as combining the two.
I have in another Mac Pro 5,1 three Samsung 850 Evo (Bay 1-3) and speeds are about 600-650 MB/s R/W (chunk size 256K)
The chunk size really matters depending on what kind of files you wanna handle on the drives.
Keep in mind that Raid 0 doesn't provide any security, it's all about performance. If you lose a single drive, you lose the entire raid.
Never happened to me with an SSD raid but I lost one HDD raid in the past (2 drives, Raid 0, one drive kicked the bucket).
So never store anything you rely on or at least always have a backup at hand.

Two Samsung Evo's in Raid 0:
Screen Shot 2018-03-01 at 14.07.18.png


Edit: Just read that you wanna use it for video. I use this kind of raid on several machines for video playback in Pro Tools.
Since videos are usually bigger files, set the chunk size to max (256K). I experienced occasional stuttering during playback when testing this with smaller chunk sizes.
 
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tsialex

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Mac Pro SATA controller itself, all 6 ports, are limited to less than 650MB/s total since EVERYTHING connected to the southbridge have to communicate at PCIe 1.0 x4, 1.0GB/s, from the southbridge to the northbridge.

Screen Shot 2019-09-19 at 10.27.03.png
 
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flygbuss

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Jul 22, 2018
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Good to know. I realized that R/W speeds will not increase by adding another drive.
But using three SSD in the SATA slots with Raid 0 still makes sense to me since SATA SSD are quite cheap and I have no use for the slots anyways.
For me the speed is sufficient and it also provides plenty of storage that way.
 

bsbeamer

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Just be careful if you're trying to use RAID in Mojave. Have ran into numerous issues with RAID0 in SATA bays with Mojave on my personal machine and in client offices with previous versions of Mojave. Some people do not report those issues, but they were abundant and reproducible.

Disk Utility > RAID assistant does appear to be working (again) in Mojave 10.14.6 18G95, but I personally have not attempted to use it recently. Changed my setup after the issues.

FYI, SoftRAID 6 still has not been released. The beta is available and does address many of the major issues, except for boot volume.
 

macguru9999

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Aug 9, 2006
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Thanks for your answers. So if someone is satisfied with about 600mb/sec they could have 3x samsung evos, say 3x2tb=6tb and back it up to a 8tb spinner in the 4th bay, with a pcie ssd as the boot drive .... and that would get you enough performance for 1k or even 2k video but probably not 4k and definitely not 8k... that is how i read the answers :)

cheers
 

tsialex

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Jun 13, 2016
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Thanks for your answers. So if someone is satisfied with about 600mb/sec they could have 3x samsung evos, say 3x2tb=6tb and back it up to a 8tb spinner in the 4th bay, with a pcie ssd as the boot drive .... and that would get you enough performance for 1k or even 2k video but probably not 4k and definitely not 8k... that is how i read the answers :)

cheers
If you want to work with 4k, buy a PCIe switched adapter like Highpoint SSD7101-A, or a newer model, and buy 4 M.2 SSDs - use one for boot and 3 for a data array.

SATA performance always will be bottlenecked by the interconnection of the south and north bridges. Apple knew that bottleneck from the start, Apple RAID card uses PCIe because of that. Apple could used the south bridge version that have Intel RAID support, but with just 600MB/s it's not worth.
 
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flygbuss

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Jul 22, 2018
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If you want to work with 4k, buy a PCIe switched adapter like Highpoint SSD7101-A, or a newer model, and buy 4 M.2 SSDs - use one for boot and 3 for a data array.

SATA performance always will be bottlenecked by the interconnection of the south and north bridges. Apple new that bottleneck from the start, Apple RAID card uses PCIe because of that. Apple could used the south bridge version that have Intel RAID support, but with just 600MB/s it's not worth.
Agreed, but it also depends. IF 600-650 MB/s meet your personal requirements it can be quite a cheap opportunity to replace the spinners and put the slots to use.
 

bsbeamer

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Sep 19, 2012
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Just mentioning - you can get about 480 MB/s write and 505 MB/s read from a SATA SSD connected via PCIe adapter without using RAID setup at all. This is fast enough for a lot of people and usually minimal investment, if the SATA SSDs are already available.

If you need larger amounts of fast(er) storage, SATA SSDs are still much more economical vs. NVMe, but obviously not as fast. 2TB models are available in both, but haven't found a single blade 4TB NVMe model yet.
 

flygbuss

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Jul 22, 2018
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Just mentioning - you can get about 480 MB/s write and 505 MB/s read from a SATA SSD connected via PCIe adapter without using RAID setup at all. This is fast enough for a lot of people and usually minimal investment, if the SATA SSDs are already available.

If you need larger amounts of fast(er) storage, SATA SSDs are still much more economical vs. NVMe, but obviously not as fast. 2TB models are available in both, but haven't found a single blade 4TB NVMe model yet.
True, but I personally find that 480 MB/s is a waste of a PCI slot. I mean if you don't need the slot anyways, fine. But in my case there all occupied with GPU, USB, NVME and AVID cards.
 

bsbeamer

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Sep 19, 2012
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And your exact scenario is why @tsialex recommended the Highpoint SSD7101-A. It really is the best option to get multiple NVMe blades into the MacPro5,1 while still being able to use the system for other PCIe cards. 1x boot/system drive and 3x storage. And in that scenario, you still have your 4x SATA drive sleds and 2x SATA drive bay available for additional SATA SSD storage, if you can live with the semi "reduced" speeds.