Slow Transfer Speeds (Internal SATA --> unRaid)


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I was fed up with the slow network transfer speeds I was getting, so I dumped a load of data on a spare 2tb drive, (ext3, I think), connected it to the SATA2 port in my unRaid appliance - mounted it using Unassigned Devices plugin, and began transferring it using Krusader.

 

However, I'm only getting 20-25MB/s - not much better than the network speed I was getting (which was via powerline adapter, so was never going to be that fast)

 

On the original machine, the data transferred onto it at over 100MB/s, and the disks are all modern SATA drives, so not sure where the bottleneck is.

 

The temp drive us plugged into the SATA port on the board (SATA2). The unRaid drives are connected to the Adaptec 51245 controller - which whilst not exactly modern, surely can't be that slow? (Documentation says 3GB/s per port). Running 2x Xeon L5520s, 16GB DDR3 Ram - no other major dockers / VMs etc.

 

The files are large (approx 1-2GB each) files - so it's not like it's thousands of small files either.

 

Am I missing something here?

 

xger2.png

Edited by extrobe
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1 hour ago, 1812 said:

have you tried turbo write?

 

 

 

I hadn't, but have now enabled it. Perhaps a modest improvement - it seems to surge up to 40-50, but then comes back down to ~30

 

Oddly, MKV files seem to transfer far faster - 110-120MB/s. Not blazing speed, but fast enough - but may just be a strong coincidence!

Edited by extrobe
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When I inquired on transfer speeds I found that unraid, well linux in general doesn't support smb multi-channel atm. It's in the works on the linux side of things but is still in a beta unstable state. So with that a gigabit ethernet network is limit pretty much to a max of 125MB/s transfer.

 

Before I decided to give unRAID a try I was using Windows server as a NAS with bonded NICs which has SMB multi-channel, transfer speeds 200+ range.

 

What I did at the advice of another user here on the forums is ordered 2x 10GB Ethernet Network Interface Cards for a peer 2 peer connection between my main machine and my unRAID server. 

 

Ordered this kit at link below which includes 2x cards and a 3m cable which is what 9 feet or something. And if you look around you can find 7m cables for around $40 bucks or so.

Another option is also transceiver module so you can use multimode OM3 duplex cables, which you can get in ranges of 30m for $40 US Bucks.

http://www.ebay.com/itm/122413899399?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

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Thanks PikkonMG

 

If I was getting 125 on a network, I'd be pretty OK with that (I won't at the moment as I'm using Powerline Adapters between the machines).

 

However the speeds I'm getting are for internal transfer speeds - not even over the network, so if 125 is achievable over the network, I'm still a little stumped as to why I'm getting such slow speeds for internal transfers.

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33 minutes ago, extrobe said:

Thanks PikkonMG

 

If I was getting 125 on a network, I'd be pretty OK with that (I won't at the moment as I'm using Powerline Adapters between the machines).

 

However the speeds I'm getting are for internal transfer speeds - not even over the network, so if 125 is achievable over the network, I'm still a little stumped as to why I'm getting such slow speeds for internal transfers.

Depend on the drives, what disk are you using? Most 7200 RPM HDD's top out around 150-200MB/s (200MB burst rate).

 

I also don't know what system you are using but I was getting inconsistent speeds with unRIAD running on my HP Proliant and it was due to some IRQ conflicts. switch my Sata and SaS to their own IRQ assignments and got about a 20% speed boost. My drive controllers, network adapters, and few other things were all on the same assignment.

 

My internal speeds with WD Reds.

2017-04-26 (2).png

Edited by PikkonMG
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The drives are a mix of Seagate and WD - Green / Blue / Barracuda etc - nothing fancy, but should be able to do better than this - driving me crazy!

 

Just done 300GB at between 7-12MB/s - taken hours!

 

Might try using cp in the terminal instead - see if that improves things, in case it's the container causing the bottleneck.

Edited by extrobe
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So rather than cp, I tried using rsync (so I could better see the speeds)

 

It wasn't any better than what I was getting from Krusader.

 

But what was interesting was that when I ran both at the same time - they weren't competing for bandwidth - but in fact they'd both track about the same speed - so if one was at 20, other other was at 20 - and if one dropped to 10, the other would as well - and speed fluctuates *a lot*

 

So I don't think it's a read issue, as it's all from the same disk. I don't think it's a write issue either, as it's all going to the same source disk.

 

So I don't know if perhaps either on on-board sata controller, or the SAS controller, is the bottleneck.

 

I used SATA port for the source drive as I couldn't get the raid card to read my existing drive without knackering the GPT partition. But I might grab an empty drive, stick it in spare bay connected to the SAS card, re-format, and run some tests from there.

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So I've been playing around with this the last few days.

 

rsync has at least been far more reliable than Krusader for transferring files - but the speed issues have not gone away.

 

I've generated a series of 1GB files on one of the disks, then used rsync to copy them to another disk - this time with all disks connected to the same raid controller. Even then, whilst I got the odd spike (for the first 10-15 seconds) of 150+MB/s, it quickly drops back down to <10MB/s

 

So would this point to a controller card issue?

 

It's an Adaptec 51245.

 

If i picked up a different raid card, would I be able to set up the disks in JBOD (as they are now), re-mount in unRaid, and retain all the data?

 

Any recommendations for a budget-ish raid card which will support 12 internal drives via 3x mini-sas?

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  • 11 months later...

I can't say I ever really got the the bottom of it. That particular build was really a POC build before I built a new server.

 

My assumption was that it was the raid card that was the bottleneck. I did try another (of the same model), and had the same issue, so might not have been, but after I transferred the setup to a new system (using the same disks, same unraid config, but PERC H200's), the problem went away.

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  • 6 months later...

Sorry for digging out this old thread, but i have the same issues here. Is there any solution for this ? I want to remove a small drive from my array and to do this i transfer the files via unbalance app with a redicoulus transferrate of 30mb/s all big .mkv and .m4v files. 

 

Turbo Write is on and the Controller is SATA II. 

Edited by cogliostro
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  • 1 year later...

Not sorry for digging up this old thread, but I have the exact same issue but on SATA 3 controllers, BUT it is also happening to USB3 hdds too, any brand.  I had a few drives in Marvell controllers and I thought they were the problem, as there's posts all over these forums saying don't use them.  I had upgraded to the 2017 version firmware of the problem controllers and all my previous issues went away and they had worked perfectly since (4 of my onboard sata ports are marvell, and the 2 ports on a PCI-E card are also marvell).

 

All that said, the only way it can explain my issues with the USB3 transfer speeds would be if both of those external drives also had marvell controllers.  How can I check this?  Or since it's been almost 2 years since the last post, maybe there's a fix for this issue now?

 

Thanks!

 

 

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