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Slow/inconsistent network performance on RAID 5 --- RAID 0 unaffected

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(@waveletmedia)
Active Member

I'm having a strange issue that may or may not be related to SoftRAID. I have a 2018 Mac mini, (Mojave) setup with a 5-drive RAID 5, (12TB WD SAS HDDs) and 2-drive RAID 0, (2TB Samsung SATA SSDs). These two raids have similar performance locally, (both around 1GBps read/write) with the RAID 5 being slightly more inconsistent which is expected.

I've setup 10gb Ethernet between the mini and my 2020 iMac, (Catalina) and I've turned on file sharing over SMB. The RAID 0 performs almost identically over the network as it does locally, but the RAID 5 performs very inconsistently on both reads and writes with the read performance averaging around 1/3 of the local performance and the write just dropping to 0MBps for seconds at a time, (see attached graphs).

I originally thought there was some kind of network issue as I had read that file sharing on Mac has had issues recently but that doesn't explain why the RAID 0 SSDs hold performance so well over the network. 

If anyone has insight into what would cause this I would love to hear it!

RAID Performance Graphs
This topic was modified 9 months ago by WaveletMedia
Quote
Topic starter Posted : 05/08/2021 6:04 pm
(@softraid-support)
Member Admin

I do know there is a 10GB ethernet bug, but I have not stayed on top of it. What ethernet cards are you using?

ReplyQuote
Posted : 06/08/2021 2:06 am
(@waveletmedia)
Active Member

@softraid-support

Both ends are OWC products.

The iMac has the Thunderbolt 3 10G Ethernet Adapter: https://eshop.macsales.com/item/OWC/TB3ADP10GBE/

The Mac mini has the Thunderbolt 3 Pro Dock: https://eshop.macsales.com/item/OWC/TB3PRODCKU/

What is the 10GB Ethernet bug?

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Topic starter Posted : 06/08/2021 1:34 pm
(@softraid-support)
Member Admin

@waveletmedia

There is a problem with macOS and some of the chipsets in Ethernet cards, resulting in very slow performance. Let me get more info.

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Posted : 06/08/2021 2:13 pm
(@waveletmedia)
Active Member

@softraid-support I'm not experiencing very slow performance on all of the shares... only on the RAID 5 disk array. The RAID 0 performs consistently well over the network. If this were a Mac OS bug wouldn't all of the shares be affected?

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Topic starter Posted : 09/08/2021 11:27 am
(@softraid-support)
Member Admin

@waveletmedia

The bug that happens with 10G is with Mohave and was fixed in Catalina. Any chance you can upgrade the Mini to Catalina?

Do that and let me know. If you still have an issue, I will give you a set of tests to try, so we can isolate what is happening better.

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Posted : 09/08/2021 12:20 pm
(@waveletmedia)
Active Member

@softraid-support

I upgraded to Catalina and it helped the write speed be more consistent but the read speed was still slow and choppy.

Screen Shot 2021 08 09 at 11.32.59 PM

 

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Topic starter Posted : 10/08/2021 4:20 pm
(@softraid-support)
Member Admin

@waveletmedia

What is your test?

A large file copy?

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Posted : 10/08/2021 4:23 pm
(@waveletmedia)
Active Member

@softraid-support

I've been testing with a 45GB movie file

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Topic starter Posted : 10/08/2021 4:25 pm
(@softraid-support)
Member Admin

@waveletmedia

a Finder copy of 45GB should be large enough to see a result.

Is this problem "bi-directional"? Is it only on reads or writes going the other direction?

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Posted : 11/08/2021 9:17 am
(@waveletmedia)
Active Member

@softraid-support

When I'm transferring to/from the RAID 0 over the network the speeds are good. On the RAID 5 I'm seeing better writes then read speeds. Writes are close to 1GB/s (which is near the local speed) and mostly consistent but reads are inconsistent and average around 250-300MB/s, (about 1/3 or 1/4 of local speed).

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Topic starter Posted : 11/08/2021 11:24 am
(@softraid-support)
Member Admin

@waveletmedia

Lets try it this way. If you unmount/swap the two enclosures, does the slow read speed follow the drives, or the ethernet connection?

(trying to isolate whether this is a volume issue, or a ethernet traffic issue.)

If it is the volume then this will repeat when you swap the enclosures.

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Posted : 11/08/2021 11:28 am
(@waveletmedia)
Active Member

@softraid-support

Both the RAID 5 and RAID 0 are in one enclosure so I can't test them separately but I can unmount them and just test the speeds to/from the mini's boot SSD which should accomplish the same thing:

The speeds are close to maxing out the 10Gb network at ~1.2GB/s read & write.

BootSSD overNetwork
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Topic starter Posted : 11/08/2021 11:51 am
(@softraid-support)
Member Admin

@waveletmedia

Mystery time. I do not know what can be causing this. I will have to see if I can replicate this setup.

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Posted : 12/08/2021 3:01 am
(@waveletmedia)
Active Member

@softraid-support

Just in case the hardware is part of the equation; I have a Helios 3 Thunderbolt to PCIe with a ATTO 1208 card that is attached to the 5x SAS hard drives and 2x Samsung SSDs.

 

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Topic starter Posted : 12/08/2021 3:02 pm
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