Super slow verify repair and unrar (ds213j)

[dmj]

i know there are topics similar to my question but I haven't been able to find anything that speaks directly to my problem - apologies if i missed anything.

I have a brand new ds213j synology nas with 2 x 3TB nas drives in Raid 1. The transfer speeds across the network are 20-30 Mb/s.

The issue I'm having is that it is taking an incredibly long time to repair and extract files using sabnzbd. The end file should be about 11gb but it has been working on the task for a long time (took about 5 hours to verify and looks like it might take 7 or 8 times as long to repair). Looking on the nas the process par2 is taking about 80% of the processor.

Is there anything obvious I can check? or should be doing to fix this issue?

Thanks for any advice

[sander]

IMHO:
verify and unrar doesn't take too much CPU power, and thus not too much time
However, repairing (par2) - if needed- does take a lot of CPU power. And if you a slow CPU (which your DS212j has) that can take quite some time. I've got a HDX-100 with a slow CPU, and repairing take hours.

So what does your logging popup when you click on the download in the History overview? Something like "Repaired in 1 minute 44 seconds" on a speedy Intel system.

I can do the same download on my Raspi, which has a slow ARM CPU too.
EDIT:
The same download (731 MB) on ARM/Raspi "Repaired in 20 minutes 46 seconds", so ARM-repair is about 12 times slower than the Intel-repair.
/EDIT

So, to avoid long repair times:
- only download posts that don't need a repair, so with all rar files available
- use a device with a fast CPU
If that's not feasible - which I can imagine - just let the repair do it's thing in the time that's needed.

[sander]

There seems to be a Dhrystone benchmark written in Python. "Dhrystone is a synthetic computing benchmark program <snip> to be representative of system (integer) programming. The Dhrystone grew to become representative of general processor (CPU) performance." So useful for the par2 repair you could get.

Get it and run it:

Code: Select all

wget http://svn.python.org/projects/python/trunk/Lib/test/pystone.py
python pystone.py

On an ARM:

Code: Select all

pi@raspberrypi ~ $ python pystone.py
Pystone(1.1) time for 50000 passes = 11.28
This machine benchmarks at 4432.62 pystones/second
pi@raspberrypi ~ $

On Intel(R) Xeon(R) CPU E5335

Code: Select all

sander@haring:~$ python pystone.py
Pystone(1.1) time for 50000 passes = 0.65
This machine benchmarks at 76923.1 pystones/second
sander@haring:~$

So the Intel is 17 times faster with Dhrystone.

EDIT:

My 3 year old i3 laptop:

Code: Select all

sander@flappie:~$ python pystone.py
Pystone(1.1) time for 50000 passes = 0.495902
This machine benchmarks at 100826 pystones/second
sander@flappie:~$ 

... so even faster.

[BladeParker]

My system started to take over an hour when verifying. This is only within the last month. I am using 0.7.185.

Nothing else has been changed on my system.