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AOC-SAS2LP-MV8 only linking at 5gbit / Very slow parity sync

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Hello,

 

I have an Supermicro AOC-SAS2LP-MV8 hooked up to 8 SATA drives.  Whilst booting, the card displays that it is only linked at 5gbps.

 

It is in a PCI-e 2.0 16x slot on a ASRock FM2A75M-ITX.

 

I have UNRAID 5.0.6 running and parity sync with these 8 drives plus another 4 hooked up to motherboard SATA ports is incredibly slow - around 20MB/sec.

 

What am I missing here - can anyone with this card confirm the speed it displays it is linked at, or suggest how to fix?

 

Thanks

Hello,

 

I have an Supermicro AOC-SAS2LP-MV8 hooked up to 8 SATA drives.  Whilst booting, the card displays that it is only linked at 5gbps.

 

It is in a PCI-e 2.0 16x slot on a ASRock FM2A75M-ITX.

 

I have UNRAID 5.0.6 running and parity sync with these 8 drives plus another 4 hooked up to motherboard SATA ports is incredibly slow - around 20MB/sec.

 

What am I missing here - can anyone with this card confirm the speed it displays it is linked at, or suggest how to fix?

 

Thanks

My SAS2LP-MV8 also display 5gbps on my mobo.  (I get ~120MB/S with 4 drives on the mobo and 7 on the card)

 

Maybe post up your syslog

The card is advertised at 600 MB/sec for each of 8 channels (lanes). That equals 4,800 MB/sec (~5GB/sec). Divide that by 8 drives and reduce by 20% for bus overhead leaves you with 480 MB/sec per drives. Not too shabby. Getting over 200 MB/sec from a drive is very rare with spinners.

  • Author

The card is advertised at 600 MB/sec for each of 8 channels (lanes). That equals 4,800 MB/sec (~5GB/sec). Divide that by 8 drives and reduce by 20% for bus overhead leaves you with 480 MB/sec per drives. Not too shabby. Getting over 200 MB/sec from a drive is very rare with spinners.

 

I suppose I misread it as 5 gbit.

 

So I guess that isn't the cause of the sluggish sync speeds...

  • Author

This is dumb.

 

When I have the web interface open during parity sync, it is slow at ~20MB/sec

 

But if I close the tab and let it run without watching, it is more like ~100MB/sec

 

Problem solved I guess.  UNRAID doesn't like to be watched while it does its stuff.

Aren't you glad it has such a nice flashy GUI?  ;D

There is a setting you need to change ...

 

Settings / Display Settings / Page Update Frequency - Change to disabled

 

This disables near continuous polling of the drives. When disabled, they only refresh on a page refresh.

 

I believe leave there is a defect / crash associated with leaving that setting turned on.

  • 1 month later...

I hate to hijack a thread, but I'm seeing sort of the same issue with an SSD drive outside of the array.

 

I've have recently installed the SAS2LP in an PICe x16 v1 slot (2.5Gbps).

 

The only drive I've added is an SATA II SSD which "theoretically" top out at 6.0 Gbps (but not in this case due to PCIe v1). All my array drives are hooked up to the motherboard with previous pre-clear results between 80-120 Mbps. Parity checks are also in the 100's once my weakest drive drops of.

 

For some reason, any file I copy to the SSD, from array, from network, from ssd -> ssd, i'm topping out at 41 MB/s (using rsync --progress, obviously not rsync over network).

 

I had much higher speeds (well over 80) for any of the aforementioned file transfers before moving the drive from the motherboard to controller card.

 

I don't see any strange log entries or errors. SSD drive properly mounts with snap.sh. I plan on adding new > 2TB drives and I'm concerned that i'll have performance reductions due to this card.

 

Any ideas?

Thanks,

Dan

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