Download speed drops to KB/s

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saintnick
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Download speed drops to KB/s

Post by saintnick » May 11th, 2018, 10:40 am

Since recently some Synology NAS users including myself are noticing that Safihre Sabnzbd 2.3.3-34 download speed will be fine for a few minutes at full MB/s and then drop drastically and stay at just some KB/s.

There's a thread (in Dutch) over at synology forum. (not allowed to paste link :-(

Speedtests with either Domotz or wget show full download speeds, for me at 13.7MB/s on my 100mb/s glass fibre connection. Also speed tests from a different device to the same usenet provider for the same content also show full speed. So it has be a local bottleneck on the NAS.

How do we find the bottleneck?

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Re: Download speed drops to KB/s

Post by safihre » May 12th, 2018, 3:12 am

Your NAS is too slow to handle SABnzbd at full speed, so it starts to use swap after a while.
Try setting Article Cache to about half of the memory in your NAS.
Then try setting the speedlimit lower. Downloading from usenet is much more CPU intense then simple wget.
For example try setting it at 5MB/s to start and see how long it stays fine like that.

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Re: Download speed drops to KB/s

Post by saintnick » May 12th, 2018, 8:29 am

Thanks, I'll try that. But as I wrote, for a couple of years and until recently (I suspect the update) Sabnzbd would always give me full 100mb/s speed without issues. So something has changed, and I'm not the only one...

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Re: Download speed drops to KB/s

Post by safihre » May 14th, 2018, 2:54 am

Could you (and others) maybe try this modified version of 2.3.3 spk-file?
https://github.com/Safihre/spksrc/relea ... bd-oldyenc (building more archs right now)
(see arch naming convention here: https://github.com/SynoCommunity/spksrc ... logy-model)

I want to identify if the problem is in the C-code or the Python code.
Thanks!

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Re: Download speed drops to KB/s

Post by morgan1993 » May 18th, 2018, 1:33 am

How come it affects the download speed?

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Re: Download speed drops to KB/s

Post by safihre » May 18th, 2018, 9:51 am

I won't know untill I get test results..

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Re: Download speed drops to KB/s

Post by saintnick » June 23rd, 2018, 9:50 am

Hi, I haven't had time until now.
I see that there is another thread for the same issue at viewtopic.php?f=3&t=23392

Again and consistently I am seeing the same behaviour on my Synology DS216+ with 1GB ram and with a 200mb/s connection.

I have tried to zoom in on the DSM resource monitor to find the bottleneck. It's not CPU or disk, nor network. The only thing I see is that Sabnzbd memory consumes up to 490-500 MB, with total memory at 80%, and then the speed drops to kb/s.

I have limited time to spend on this. Which SPK should I try (the one you give above is 404)? And how exactly is a special build going to help you identify the issue? Does is upload info to you? I would expect you to be asking for a debug log instead of installing a new build.

Regards,
Nick

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Re: Download speed drops to KB/s

Post by saintnick » June 23rd, 2018, 12:22 pm

I reduced Article Cache from 227 MB to 100 MB, which seems to show a bit better performance, but nothing like I was used to.

I would like to try to get back to the previous version I had installed which gave flat max line performance, but how do I found out which version that was? I always installed latest through Synocommmunity. I would guess whatever release for January was available on Synocommunity?

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Re: Download speed drops to KB/s

Post by saintnick » June 23rd, 2018, 1:45 pm

Tweeking server connections and article cache seems to do something, and improvement, but a previous version just worked out of the box. I don't have the time or patience to figure out exactly which combination of server connections and article cache will give me max throughput.

With 3 connections and 100 M article cache I'm now getting 80% erratic max line speed as opposed to 100% flat line speed with previous version. So whatever was added in new version (sabyenc?) is no improvement on my system.

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Re: Download speed drops to KB/s

Post by whitlee » June 30th, 2018, 11:29 am

I am a newbie and have read through this thread as I am experiencing the same problem the speed ramps up to about 80 MB/SEC for about a few minutes and then slowly falls to about 17 MB/sec, have been fighting with the provider but after reading this i don't think it's them, looking to see if anyone has figured out what the problem might be. Also ever since i put this newest version on it just sits after the download is finished and no processing takes place have to leave it for quite a long time before it drops out of the download bar and unpacks, don't seem to see the verifying or repairing anymore, is that what is going on behind the scenes then drops down and unpacks.

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Re: Download speed drops to KB/s

Post by saintnick » June 30th, 2018, 11:39 am

Whitlee, I am trying to contact Safihre for instructions as to how to help him pin down the problem.
Meanwhile can you give two bits of info?
1. which is the last version you had which did NOT display this behaviour?
2. what hardware and os version are you on? (I am on Synology DS216+ with DSM 6.2)

Update:

Safihre just gave this info:

The URL should work again: https://github.com/Safihre/spksrc/relea ... bd-oldyenc (arch here: https://github.com/SynoCommunity/spksrc ... logy-model)
It is building them now, so needs maybe another hour for all of them to be there.

Can you test and see if you get the old speeds back? Your settings should be preserved.

Let's both try and test.

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Re: Download speed drops to KB/s

Post by whitlee » June 30th, 2018, 12:58 pm

Saintnick

I am running version 2.3.4, I have only had the fibre for a couple of weeks running on this version, the previous version would have been 2.3.3 running on cable at a much slower speed and I didn't have any issues.

I am running High Sierra ver 10.13.4 for an OS, not sure what you mean by hardware?

Will try out that link once it finishes unpacking , been waiting for about 15 minutes and it finally started unpacking

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Re: Download speed drops to KB/s

Post by whitlee » June 30th, 2018, 1:20 pm

What do I use for a user name and password for this link or do I have to join GitHub to create one

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Re: Download speed drops to KB/s

Post by saintnick » July 2nd, 2018, 5:23 pm

Whitlee, wait a moment. A few things:

There were some glitches with the links that Safihre posted, he told me in PM.
You probably downloaded the source code, you don't want that. The link you need is here, for the SPK install package of the old version without the new SabYenc: https://github.com/Safihre/spksrc/relea ... bd-oldyenc

From that page you need to select, download, and install the correct SPK package for your hardware. From your question "what do I mean by hardware?", it means brand or make (actually: processor architecture) of your PC. In your case it is an Apple Mac. For me, for my Synology DS216+ with Intel processor it was the "sabnzbd_x64-6.1_2.3.4-36.spk". For you, I don't know, you need to google. Or maybe someone else can tell you which you need.

Anyway, I downloaded and installed mine, and will post the results separately hereafter.

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Re: Download speed drops to KB/s

Post by saintnick » July 2nd, 2018, 5:35 pm

safihre wrote:
May 14th, 2018, 2:54 am
I want to identify if the problem is in the C-code or the Python code.
Thanks!
Safihre, I finally was able to install the version you intended to link to. And the results don't surpise me but will disappoint you.

I immediately got back to my flatline max DL-speed of 200 mb/s, 24,2 MB/s :-) See this graph:

Image
https://imgur.com/a/LzFkM6p

The first part of the graph is the sabnzbd-oldyenc with just three connections (which worked best for your new version with SabYenc). This gave 21-23 MB/s which was already much better. Then I switched to my normal 12 connections, and got back my familiar flatline 24,2MB/s
Also worthy noting is that in my DSM resource monitor, only 52% of memory was consumed, in contrast to before where SabNZBd would push it above 80%.
This is bad news for SabYenc.
Please consider fixing, as I am not alone in this...
If I can be of any assistance, with logs or so, let me know.

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