Synology DS1512+ DLs start fast then slow to a crawl

[crispyal]

Running SABnzbd+ 0.6.15 on a Synology DS1512+ (with 4GB ram) using python 2.6. This is running alongside Sickbeard, Couchpotato and Subsonic (java based).

My issue is as follows - any file, any size, any time can be affected regardless of queue length. Upon a reboot of SABnzbd itself (or the NAS) I can expect speeds in excess of 2.5MBs as a rule - within about half an hour this sometimes drops to less than 300kbs (sometimes even lower). Reboot SAB and the issue goes away again for another indeterminate length of time.

Other info about my setup - I have a 100MBs line from Virgin UK on Giganews + Astraweb using port 443 with SSL. If I run SAB on my desktop with gigabit ethernet connected I can expect (almost always) SABs readout to exceed 11MBs. In other words, it's not my line!

I have tried several different configuations of sab.ini files - creating them from scratch as well as copying them over from my supposedly known good desktop installation getting 11MBs but just changing the paths accordingly.

Is this a bug? Or should i just put up with restarting SAB every 30 mins or so?

[sander]

Related to the Dutch synology thread with 'stabiel' in the subject? I'm on my tablet and I don't know how to copy an URL.

[crispyal]

Ive put those threads through google translate and tbh don't really get much tangible info back.

Some stuff about timeouts. What should I adjust if anything? Incidentally my Sab has fallen to 150k since my last post.

[crispyal]

http://forums.sabnzbd.org/viewtopic.php?t=10638

For refernce.

[sander]

Can you install another nzb downloader on your synology and see how that behaves?

How many connections do you use? I would say five are enough.

[celestian02]

Hi,
I am experiencing the same kind of issue with my Synology 1512+. So far, I have read that many encounters slower download speeds with SABnzbd and I am kinda frustrated because I really do love my SAB!

As for my esperience: I recently switched over to FO and had my SAB install previously on a Mac Mini and was getting 136Mbit/s.
More recently, I bought a Synology 1512+ and had SABnzbd installed through the Synocommunity package. SAB itself is behaving perfectly well but I'm only getting, at max: 56Mbit/s. So one would argue that I should not complain with that kind of speed. Fact is that when you know you have more, you always want more And more seriously, I get a drastric 40% loss in download speed performance! Kinda frustrating.

At first, I thought it was my NAS but I ssh to my NAS, did a wget on some ftp website and did reach my 136Mbit/s.

Now, I read some article and found out about the max # of connection, the cache articles: Reduced from 20 to 6 until I started to see a decrease in my 56Mbit/s download speed. Then started playing around with the cache setting from null to 100M. Nothing has either improved or worsen...

I also want to add that at no moments, my NAS gets overloaded. Overall memory usage is at 30% and CPU usage never gets passed 50% at max.

Has anybody got any idea? Thanks for your inputs!

[sander]

I also want to add that at no moments, my NAS gets overloaded. Overall memory usage is at 30% and CPU usage never gets passed 50% at max.

Has anybody got any idea? Thanks for your inputs!

Can you try nzbget on your Synology and see which speeds you get?

[celestian02]

Hi Sander, thanks for your quick reply. Just tried this out and I do get my 136Mbit/s with NZBget but it hurts my eyes compared to SAB, ahah...

[sander]

Hi Sander, thanks for your quick reply. Just tried this out and I do get my 136Mbit/s with NZBget

So ... line speed with nzbget? Cool. Good to know.

Oh: is NZBget also fast during repair and unrar? That takes a lot of CPU power.

but it hurts my eyes compared to SAB, ahah...

Hahaha, that's true.

SABnzbd is written in Python, which is less fast and takes more CPU than programs written in C (like NZBget). So: you have to choose: pretty or fast ...

[celestian02]

So ... line speed with nzbget? Cool. Good to know.

Yeah linespeed with NZBGet... Although I don't think that would make me leave SABnzbd for it

Oh: is NZBget also fast during repair and unrar? That takes a lot of CPU power.

Did not monitor extraction though.

SABnzbd is written in Python, which is less fast and takes more CPU than programs written in C (like NZBget). So: you have to choose: pretty or fast ...

Yup, I do know that. Python has proven to be my first language I would choose whenever I need to develop something. However, while it's true about python performance compared to C programming. That does not seem like a satisfying reason, would't you agree?

I mean, on a Mac Mini, I do get this speed and it's also python on Mac. It's true that the Mac has got more horse power (CPU:i5 2.2Ghz / Memory:8Ghz), but at, using my NAS, at no moments while downloading, my CPU gets near 50% usage, so it does not seem like it's being limited by the NAS hardware...
I would even say that when I reach 50%, it's because it's downloading while post-processing a former download!

[sander]

I checked specs of the Synology DS1512+'s CPU:

"CPU Frequency : Dual Core 2.13GHz" (http://www.synology.com/products/spec.p ... #p_submenu)
Intel Atom D2700 Dualcore (2C/4T) 2.13GHz x86 Processor 64-bit@DDR3, 1GB of RAM (source http://forum.synology.com/wiki/index.ph ... y_NAS_have)

So ... that doesn't sound too bad. But as you say your CPU load is below 50%, I don't know what you can do to get a higher speed.

[celestian02]

Strange things, it sure is. There is no apparent reason =) But thanks for looking into it!

[powertowerpro]

I am experiencing a similar problem. I have DS1812+ and am on a 100Mbps line. I normally max out SABnzbd at 10MB/sec on my desktop. I recently switched to the Synology Package available at http://www.synocommunity.com/packages

Now I get 4MB/sec max, and often much lower. The Synology has 1GB of memory and the CPU never goes higher than 45%. Any ideas on what could be causing the difference in speed?

[shypike]

and the CPU never goes higher than 45%.

Is this a dual-core system? SABnzbd can only use one.
Other than that: there are just so many differences between a NAS and a PC.

[celestian02]

Hi Shypike,

Well, no it's not a dual core. I agree with you that because of this difference, it can be caused by so many different things. Still, I find it surpising for the many reasons I have listed and we are talking about performance differences between a Linux based operating system (Synology DSM 4.1) and a Unix based operating system (Mac OSX 10.8.1) on which both Python is running.

I have continued testing with different News Providers and always the same thing, seem to be capped at 7MB/s while I can reach 17MB/s on my Mac Mini (w/ SABnzbd) and Synology (w/ NZBGet)


running Python with a Unix

to your remarks but this is still surprising that a Intel architecture running on a somehow linux operating system based on a linux kernel would behave that much from a Mac OSX (Unix)