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slow downloads with NAS

Posted: June 17th, 2012, 4:43 pm
by nimdjid
Hi

I got a new synology DS411 NAS with latest firmware and I got version 0.7.0 of SABnzbd installed on it.
Im using 7200rpm HDD drives in a RAID5 config.
Im downloading torrents from this NAS in around 8MB/s and from my desktop I normally do around 10MB/s.
However when using SABnzbd from this NAS I can only reach around 2-3 MB/s. Ive tried lowering number of connections to my usenet provider from 30 to 15 and it didnt make any difference. The CPU of 1.6ghz is basically maxed out constantly during downloads..

Is there anything to do here..?

thx

Re: slow downloads with NAS

Posted: June 18th, 2012, 1:17 am
by shypike
Not much, Usenet costs more resources than torrents do.
Plus, SABnzbd isn't the fastest program around.
If you have enough memory (say 1G), you should set an article cache
of about 200M in Config->General.
This will reduce disk access (which in the case of RAID5, will make a difference).

Re: slow downloads with NAS

Posted: June 18th, 2012, 2:30 am
by nimdjid
I have 512MB RAM. Should I try some cache for this?
My disks also has 64Mb cache (Im no computer expert so have no idea if thats gonna be useful). My disks are 4x this one: 3TB Seagate Barracuda 7200rpm SATA 6Gbit/s - ST3000DM001

Also could I benefit from doing any setting in my synology DSM (obviously dont expect you to have answer for this in this forum, but IF you do please let me know, cus theres an option for turning disk cache onn/off)

Re: slow downloads with NAS

Posted: June 18th, 2012, 4:09 am
by shypike
Disk cache is always useful, but less relevant here.
The thing with RAID5 is that it will start creating redundancy for files
that will be on disk less than an hour.
The article cache will prevent that lots of small temporary files will be created.
Depending on what type of you download, consider setting the cache to 128M.
In any case, you will not get impressive speeds. SABnzbd just needs too many resources for that.
This isn't a problem on a modern desktop or laptop, it is on most embedded systems.

Re: slow downloads with NAS

Posted: June 18th, 2012, 4:40 am
by sander
You could try out nzbget on your NAS. It might even be built-in ... See http://www.nascenter.nl/product/115770/ ... s411j.html (warning: Dutch).

nzbget is less beautiful than SABnzbd, more difficult to setup, but it requires less resources. So possibly a solution for your NAS.

Re: slow downloads with NAS

Posted: June 18th, 2012, 4:45 am
by nimdjid
Thx for the advice

You think it can handle all the things Im planning to use the SABnzbd for? My plan was to use it together with sick beard, couchpotato and headphones + Iphone apps.
I want the functions to auto unrar and rename and move to different folders also..

thx

Re: slow downloads with NAS

Posted: June 18th, 2012, 6:11 am
by sander
nimdjid wrote:Thx for the advice

You think it can handle all the things Im planning to use the SABnzbd for? My plan was to use it together with sick beard, couchpotato and headphones + Iphone apps.
I want the functions to auto unrar and rename and move to different folders also..

thx
I don't know: I only use SABnzbd (and nzbget on my mediaplayer), but no sickbeard, couchpotato etc etc.

Rule of thumb:
If you want easy setup and usage and lot of functionality, use SABnzbd. It requires CPU and RAM power.
If you have low CPU and/or RAM, and can handle its setup, use nzbget. It results in basic functionality: downloading. Even the par/unrar stuff requires extra setup.

Re: slow downloads with NAS

Posted: June 19th, 2012, 7:35 am
by nimdjid
I dont see it using a lot of CPU unless you use the article cache, which I tried, and it actually did change a little bit.. like couple hundred kb/s.. Still like 5mb/s missing to get to the synology built in downoadstations speed

Re: slow downloads with NAS

Posted: June 19th, 2012, 3:57 pm
by Nillaz
Can anyone with a working knowledge of Sab give me a better understanding of how it utilizes existing CPU and RAM resources? Is it scalable in the sense that it will utilize everything you can throw at it before other bottlenecks become the limiting factor (ie. disk write speeds, connection speeds, etc.) , or is there an upper limit to what it can achieve for maximum efficiency?

I mainly ask because even amongst comparable setups on a Synology NAS there seems to be a discrepancy as to how well Sab performs. Using an identical NAS (DS411) I can saturate my connection and consistently achieve solid 4 MB/s downloads while others are getting significantly lesser speeds (2-3 MB/s) on better internet connections.

Re: slow downloads with NAS

Posted: December 26th, 2012, 5:40 am
by jrdevisser
Have you tried to to set the cache limit? worked for me!

http://wiki.sabnzbd.org/highspeed-downloading

Regards Jeroen