Very slow transfer speeds between disks

[extrobe]

Hi, after a bit of advice.

I'm getting very slow transfer speeds when writing to disks attached to my RAID card.

Whilst I might get the odd burst of 150MB/s+, I average at 5-10 - and am trying to understand;
1 - Whether this is expected behavior
2 - Whether this is down to the RAID controller
3 - What I can do to improve it

Hardware:
Tyan S7012 board with x2 Xeon L5520, 24GB DDR3 Ram
Adaptec 51245 SAS controller connected to 12 SATA drives via 3x Mini-SAS-->4xSATA
Multiple WD 4TB Green disks, all empty, formatted as xfs, setup in JBOD within the controller

OS:
unRaid 6.3.3, with 1 parity disk
Couple of dockers running, but nothing intensive, no VMs, no Cache disks etc

The Tests:
I created a series of 1GB dummy files in the root of one of the drives, then used rsync to copy them to the root of another drive attached to the same controller. (I've also used other utilities for moving / copying, and tried copying from a drive connected to the standard sata port - the results are all consistent)

The attached file shows the results from transferring the files. I know I'm not using the fastest drives, or the latest hardware - and i know there'll be some overhead from writing to the parity disk (but get the same issue when writing to the disk on the sata port which does not fall under the parity disk anyway) - but surely these can't be the right speeds?

The drives themselves seem to operate fine when I use them in my Ubuntu microserver - so I'm leaning to the raid card being the culprit here. Is there anything else obvious i should rule out?

What would be best course of action be? Replace the raid card? Is there an alternative model I should consider? (On a bit of a budget!). I've only had the kit a couple of weeks - is it worth dropping the vendor a note, seeing if they have a replacement?

I don't need break-neck speeds, but need better than 5-10MB/s

 

[i386]

I can't say something about unraid or linux software raid in general but about the wd greens. These drives are terrible, I had problems with my 3tb greens to sustain 50+ mb/s with sequential workloads.

The drives themselves seem to operate fine when I use them in my Ubuntu microserver

Did you test the "performance" there? Otherwise I would blame the drives.

 

[extrobe]

I can't say something about unraid or linux software raid in general but about the wd greens. These drives are terrible, I had problems with my 3tb greens to sustain 50+ mb/s with sequential workloads.


Did you test the "performance" there? Otherwise I would blame the drives.

Although most of the drives as WD Green, they're not all - there are a couple of Seagates for example - and I get the same results regardless of which drives I'm using.

And yes, the Ubuntu system copies/writes at over 100MB/s (it's only a celeron based system) using the same drives (as that's the system I'm migrating the data from). So I hear what you're saying about the drives, but have tried to rule them out as being the issue. In all honesty, if I had around 50MB/s, I'd be pretty happy )

 

[Rand__]

Have you tried using the onboard sata controller for 2 drives to get a reference?
No clue re unraid, so maybe not possible if you have to pass on...
Maybe get a cheapo BR10 (3GB/s-> cheap) to test?

 

[extrobe]

Have you tried using the onboard sata controller for 2 drives to get a reference?
No clue re unraid, so maybe not possible if you have to pass on...
Maybe get a cheapo BR10 (3GB/s-> cheap) to test?

That's certainly next on my 'to check' list - need to grab another sata power splitter first though!

Might also drop the vendor a note as well with what I'm seeing - see if they have any suggestions.

 

[extrobe]

The attached images show the PCI area.

I guess, with the 'right' riser (if such a thing exists), there's probably about enough space for 2 cards in the horizontal position - the current one is pretty much flush with the lid, so there's a fair bit of room beneath it.

The current riser does have an additional slot - a legacy PCI slot I presume.

 

[extrobe]

Would something like this riser card work?

 

[PigLover]

Would something like this riser card work?

That will only work if the MB supports bifurcation of the PCIe slot.

Sent from my SM-G950U using Tapatalk

 

[PigLover]

It is curious that you are using that MB in a WIO/UIO chassis. Are you doing that just so that you can use a full height card in a 2u chassis? By doing that you strand/waste the other PCIe slots on the MB.

If it were me I'd replace the rear window of the chassis with a 'standard' LP configuration, ditch the raid card and riser and replace them with 2 LSI-based HBAs running in IT mode.

Sent from my SM-G950U using Tapatalk

 

[extrobe]

It is curious that you are using that MB in a WIO/UIO chassis. Are you doing that just so that you can use a full height card in a 2u chassis? By doing that you strand/waste the other PCIe slots on the MB.

If it were me I'd replace the rear window of the chassis with a 'standard' LP configuration, ditch the raid card and riser and replace them with 2 LSI-based HBAs running in IT mode.

The chassis /MB setup all came 'as-is'. With the benefit of hindsight, a little bit more research and I'd have perhaps sourced the parts individually and would have been able to avoid much of this!

I've been searching for a replacement window, but not much luck so far.

 

[extrobe]

Although, this looks like it might be the rear window I need!

Actually, I don't think that's quite the right one - but I'm on the right track!

 

[PigLover]

Is it a supermicro chassis (it appears to be...)? Thrn that chenbro rear window is def. the wrong one.

Post a picture of the entire rear of the chassis, including the psu.

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