SATA VM Passthrough speeds slow


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Hi all,

 

I created a windows VM to do some Chia storage plotting.

I added a manual vDisk as: /dev/disk/by-id/ata-INTEL_SSDSC2KB019T8_PHYF016402MC1P9DGN

With SATA as the Bus.

 

But when reading/writing to the disk its going at around 100MB/s.

But SATA should allow around 500MB/s. 

 

The same drive on a dedicated PC gets full 500MB/s.

 

Is there any way I can pass it through to the VM where I can read and write at almost full speed?

Windows is showing it as QEMU Harddisk if that helps anyone. Or does it need specific drivers? 

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46 minutes ago, SavellM said:

Is there any other way to get faster perf?

No idea, I will do some test for compare.

 

46 minutes ago, SavellM said:

I cant split IOMMU group as its part of my backplane :(

SSD can place anywere, it use little space. Some PCIe SATA controller card also cheap.

Edited by Vr2Io
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Seems not a cheap RAID card, hardware RAID usually not recommend, if it is AHCI type then Unraid may be work with it, if not, you need driver support. But even work, it just like a black box, no SMART monitor possible on the disks.

 

If you have M2 slot, why don't simple go to NVMe ?

 

Or why don't buy some cheap Asmedia 2 port SATA controller card, lowest price could be 10usd.

 

Pls note, IOMMU standalone or not almost not relate the card itself, it relate on CPU and Motherboard always.

Edited by Vr2Io
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Ah thats a good point about the cpu/mobo. Is there any way to know before it arrives?

I liked this one as no cables or anything, just strap it on. I found a few cheaper but they all seemed to cap out at 400MB/s even with 2 drives.

 

Why not go NVMe, because I already have 2x2tb SSD's and need space and some speed.

2x2TB NVMe is going to be pretty expensive. 

But I am looking at some now with a m.2 PCI-e card too, so maybe I'll end up doing both in the future.

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For speed and capacity need, I will use spinning disk in 4 disk RAID0 (BTRFS RAID), it have 400MB/s+, I even try 10 disks RAID0, it have 1.5GB/s performance. I use it as backup data purpose.

 

The real problem was vDisk performance to VM drop too much.

 

You need storage under VM ? Can't simple provide by Unraid ?

Edited by Vr2Io
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13 minutes ago, Vr2Io said:

For speed and capacity need, I will use spinning disk in 4 disk RAID0 (BTRFS RAID), it have 400MB/s+, I even try 10 disks RAID0, it have 1.5GB/s performance. I use it as backup data purpose.

 

The real problem was vDisk performance to VM drop too much.

 

You need storage under VM ? Can't simple provide by Unraid ?

I'm trying to plot Chia (crypto currency) It needs fast SSD/NVMe storage, and quite a bit to plot a lot in parallel.

Currently passing through SSD via emulation is taking me like 24hours to do 1 plot, but same drive on my dedicated PC is taking like 7 hours to do a plot.

So I'm trying to cut the plotting time down via my server as I can do a lot more in parallel.

 

After it does the plotting, it then moves that file to my unRAID storage array.

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Just now, Vr2Io said:

Understand, seems need high performance random I/O storage and under VM.

Yup bit of a pickle :)

 

I have quite a few threads and a lot of ram on my server. 

But passing through SSD perf just doesnt seem to be there. 

Really hope that PCIe card will be in its own IOMMU group then it should be good.

I think I should be ok, looking through my current IOMMU's seems like just about everything is in its own group.... I think

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4 hours ago, Vr2Io said:

FYR, test on SATA vDisk got 130MB/s, performance not consistence with deep drop.

Yup thats what I'm seeing...

Perf is not consistent at all... It might hit 130MB/s sometimes I've seen it scape 250MB/s very briefly and then drop.

But latency to the drive is really bad.

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