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RAID 0 with 3 drives only has 2x performances

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(@burningman)
Active Member

Setting:

- 3x Samsung QVO 870 8TB

- Thunderbay 4 Mini enclosure

- macOS 12.2.1

- SoftRAID 6.2.1

 

BlackMagic speed for each drive individually ~520MB/s.

RAID0:~1000MB/s

RAID4: ~700MB/s

 

I would have expected RAID0 performance of around ~1.5GB/s and had hoped for RAID4 around ~1GB/s. Is this performance expected or is something wrong? What performance could I expect with a 4th drive?

Also, why do I need to restart SoftRAID after disabling safeguard to have it have an effect? Is that intentional?

Quote
Topic starter Posted : 01/03/2022 12:29 pm
(@softraid-support)
Member Admin

I would expect better, also.

 

You can create a RAID 0, then use SoftRAID to convert to Apple format. Then you should see the same performance.

 

I would use AJA system test (app store), as it is more consistent. Settings would be:

Codev RGBA

Resolution 5K (or higher)

File Size 64GB or 16GB

With AJA you can expand the chart and see if there are dropouts affecting performance.

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Posted : 01/03/2022 4:23 pm
(@burningman)
Active Member

@softraid-support

What do you mean by "create RAID 0, then use SoftRAID to convert to Apple format". The RAID0 volume I created in SoftRAID is already APFS.

AJA (5K, 16GB, 16bit RGBA) results:

SingleDrive:

RAIDNone

RAID0 (3 drives):

RAID0

RAID4 (3 drives):

RAID4
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Topic starter Posted : 02/03/2022 2:01 am
(@softraid-support)
Member Admin

@burningman 

that is horrible write performance. Do you get the same with RAID 5 volumes?

This is an M1, correct? Write performance is slower as M1 performance on disks is not as good as on intels, but this is way too slow.

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Posted : 02/03/2022 2:07 am
(@burningman)
Active Member

@softraid-support 

Yes, this is on an M1 Pro. Results for RAID5 (3 drives) are here:

RAID5

 

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Topic starter Posted : 02/03/2022 2:15 am
(@softraid-support)
Member Admin

@burningman 

What is the model number of your Mini?

 

If I have one, I can test this, but I have seen better results with 5 year old SSD's.

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Posted : 02/03/2022 11:43 am
(@burningman)
Active Member

This would be owctb43mini or owctb3qmsr00gb (not sure).

Interestingly, in RAID4 mode the write speed almost doubles when I connect a second TB cable to the mini?

What speeds would you expect when I add a 4th drive?

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Topic starter Posted : 02/03/2022 4:32 pm
(@softraid-support)
Member Admin

@burningman 

Clarify what you mean by a second cable?

 

With 4 drives writes should be close to 2.5-3X , and reads 3X a single drive.

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Posted : 02/03/2022 4:35 pm
(@burningman)
Active Member
Posted by: @softraid-support  

With 4 drives writes should be close to 2.5-3X , and reads 3X a single drive.

4 drives, RAID4, single cable, 0.75x writes, 2x reads:

4xRAID4

4 drives, RAID4, second TB3 cable between Macbook Pro and Thunderbay 4 Mini, 1.3x writes, 2x reads:

4xRAID42ndCable

 

Clarify what you mean by a second cable?

Well, just that, when I connect the Macbook Pro with the Thunderbay 4 Mini with two cables instead of one, I get better write speeds. (Interestingly read speeds don't change)
 
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Topic starter Posted : 03/03/2022 7:24 am
(@softraid-support)
Member Admin

@burningman 

What if you only use the second cable?

I would not expect cables to work (interference), I have to check this out.

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Posted : 03/03/2022 9:54 am
(@burningman)
Active Member

@softraid-support 

Makes no difference which cable I choose, results are consistent based on the number of cables.

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Topic starter Posted : 03/03/2022 11:04 am
(@softraid-support)
Member Admin

@burningman 

Let me ask some hardware engineers about this. Its weird, and I would not have believed possible.

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Posted : 03/03/2022 11:37 am
(@softraid-support)
Member Admin

What are the two cables? How long is each?

Do both have a "3" on them?

One idea might be one is passive, the other active, but it would not explain the write speed changes.

Run SoftRAID. Zero disks. (100 sectors)

run DiskUtility/RAID Assistant. Create a RAID 0 volume. What numbers are you getting?

If different, "convert" to SoftRAID (volumes menu, restart and retest.

 

let me know.

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Posted : 03/03/2022 12:26 pm
(@burningman)
Active Member

both are TB3 cables with 3s on them one, not sure if active or passive. both ports have the same specs in the system profiler.

creating the raid0 in diskutility does not result in different performances. should i open a dedicated support ticket outside of this forum?

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Topic starter Posted : 03/03/2022 3:26 pm
(@softraid-support)
Member Admin

@burningman 

 No need. Both are same length cables? (.5m 1m or 2m?)

OWC branded cables or other?

this is clearly a hardware issue, as you see. SoftRAID gives the same results as Apple's RAID. I hve some of our SSD's in stock, I can test with. It may be something weird with the Samsung and the mac. If these are the "latest" 870 drives, Samsung is often not mac compatible in first releases of hardware.

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Posted : 03/03/2022 3:50 pm
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