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Slow sabnzbd downloads

Posted: December 9th, 2018, 3:23 pm
by regder
I have sabnzbd installed on both my Arch Linux server and my Macbook. The server is the one with a speed issue. Internet is 1000mbps, and consistently get speedtests around 600-700mbps. With my Macbook connected to my wifi, I get 25-30MB/s. If I reboot the server, I get similar speed for a bit, before it drops to an average of 3MB/s, where it stays. Well seeded torrents regularly download at 20MB/s on the server. Recently upgraded the router with no change in speed.

A few details on the server
- Asus ChromeBox M004U running Arch Linux, minimal hardware but works great for everything I need, well except this
- Hardwired to my gigabit router
- Latest sabnzbd
- Downloads to NAS that is hardwired to router

Re: Slow sabnzbd downloads

Posted: December 10th, 2018, 4:30 am
by sander
In SABnzbd, if you click the Wrench symbol, and then the refresh symbol, what do you get for

System performance (Pystone)
Download folder speed
Complete folder speed

Re: Slow sabnzbd downloads

Posted: December 10th, 2018, 12:40 pm
by regder
System performance (Pystone)88707 Intel(R) Celeron(R) 2955U…
Download folder speed27.1 MB/s (/mnt/Incomplete)
Complete folder speed27.7 MB/s (/mnt/Completed)

Re: Slow sabnzbd downloads

Posted: December 10th, 2018, 12:51 pm
by regder
I think I may have figured out the issue when looking at that Wrench display. The connections display goes from 20/20, the full amount setup for the server, incrementally to 0/20 before going back to 20/20 and repeating. This is happening continuously when downloading.

Sabnzbd on my Mac keeps a constant 20/20 connections as it's downloading.

Don't know how to fix that though

Image

Re: Slow sabnzbd downloads

Posted: December 10th, 2018, 4:48 pm
by sander
set logging to +Debug,
do some downloads,
check the log

Re: Slow sabnzbd downloads

Posted: December 10th, 2018, 8:11 pm
by regder
I'm seeing a lot of "[downloader:287] Delaying"

https://pastebin.com/MHTU925A

Re: Slow sabnzbd downloads

Posted: December 11th, 2018, 2:24 am
by safihre
Your CPU can't keep up decoding and writing to disk the stream of articles being downloaded.
Try reducing the number of connections to 10 and setting the Maximum line speed in Config > General a bit slower than your max, try for example 10MB/s at first.

How much memory does this box have? I see on Amazon it's 2 GB? In that case I would increase Article cache to 1GB.

Re: Slow sabnzbd downloads

Posted: December 11th, 2018, 4:04 am
by sander
I would also be interested if you use an internal or USB-external disk connected to youAsus ChromeBox M004U

Although your NAS shows 27.1 MB/s, which is not very bad, a internal/USB-external disk is always faster.

Re: Slow sabnzbd downloads

Posted: December 11th, 2018, 11:27 pm
by regder
I think I have come to the conclusion that my server is just too slow. The ChromeBox has 2GB ram, and there's a 2Gb swap file.

Plugged in an external hard drive, and directed nzbs to there. Testing at 35MB/s. Set connections to 10, article cache to 1GB, max speed to 10MB/s. Now I can get a steady 10MB/s, but the second I try to crank things up, everything slows down.

At 20 connections and 15MB/s speed, I think I'm running at max.

I'm going to offload Kodi that also runs on the server and see if that gives me more buffer room

Re: Slow sabnzbd downloads

Posted: December 12th, 2018, 12:27 am
by regder
Playing with it some more. It appears that once Sabnzbd runs into a road block, not sure if it's ram or cpu, it starts running at a snails pace regardless of settings or available resources. Restarting Sabnzbd with reasonable restrictions brings it back to speed. As long as it doesn't run out of resources, it stays fast

Re: Slow sabnzbd downloads

Posted: December 13th, 2018, 2:12 am
by safihre
You are right: at some point the cpu can't keep up and we store new articles in memory, but when that runs out we have to put them to the disk. This is slow because we have to write, but also read them in again and then delete the file.
This Christmas holiday I hope to create a solution for this, but it requires some core changes.

Re: Slow sabnzbd downloads

Posted: January 4th, 2019, 6:52 pm
by regder
Forgot to update this. Upgraded to 4gb of ram over the holidays and the problem is solved. Can now download at 60-70MB/s without issue.

Thank you guys for the help!!!

Re: Slow sabnzbd downloads

Posted: January 9th, 2019, 2:18 am
by alanperker
Facing the same issue

Re: Slow sabnzbd downloads

Posted: January 9th, 2019, 2:44 am
by safihre
Have you tried the things suggested in this post?