MBP Late 2011 freezes under yosemite I have an MacBook Pro Late 2011 and it freezes (So the Beachball is turning arround), not completely randomly but when I use the disks, (writing or reading data) over 1/2 Mb/s so if I copy a big file from a DMG it freezes often but randomly during the copy process, or if I download something over internet it freeze randomly during the download.
I can't do anything except of moving the mouse, if i wait a few seconds all comes back and I can continue use my Mac. I first thought it was totally random but it happens more often when I copy data or download anything. I think it's Yosemite's fault but I can not certify that.

Useful pasts: 

EtreCheck: https://paste.ee/r/UvuNe

Full console log: https://paste.ee/r/kxZgs

I already reinstalled OSX Yosemite, and after that it continued with the same issue, but before i reinstalled a fresh version, it hung up always randomly, after I reinstalled OSX on my Home made Fusion Drive it only hung up when i started copying files or other things like that

I have read similar topics on internet about Yosemite and Freezing bug that was always different causes and different freezes like total freeze (no mouse) or freeze for infinite time and does not continue after a few secs.

When it freeze ALL stops even iTunes stop playing music. and after the freeze stops, everywhere i clicked clicks in a accelerated mode.
So if during the freeze i click on two apps and open a few menus, it does nothing but after a few secs all opens.

Anyone got the same issue or an idea to solve/troubleshoot this ?

Sorry for my English.

Edit: (my answer to  Buscar웃SD)
I already looked at the system monitor, i forget to say it i'll add it.
When the freeze happens the CPU is at 30% and disks are not at 100% when ii download but when I copy anything they are at 100% So it's weird, the amount of RAM used changes nothing, and the console writes nothing suspect

Edit2: I add a few images from the console and activity monitor during a freeze:

During the Freeze



Another during the freeze



And this is after the freeze



I have another screenshot who is important and it's the lines during the FREEZE, theses lines are these after the blue selected line
On the screenshot we can see that the freeze during from 20:20:58 and the next line appears on 20:21:07 so the crash is during 9 seconds:
So, I installed OS X EL Capitan, (10.11) and i started to transfer a 9Gigs app (xCode) to install it, and I had NO freeze, so it is Yosemite, and fixed in OS X El Capitan :)  It was only a quick test but On Yosemite doing this froze the system every minute. 
If I get one freeze during the next days I'l Edit this post. If not I resolve it.

Anyway, thank you for your help :)

Okay it wasn't OS X but Hardware, The second SSD was installed in the Optical Super Drive bay, and on Late 2011 Mac Book Pro there is an issue on the controller so I installed OS X on the Hard Drive without using the SSD, NO freeze, so I decided to swap SSD and Hard Drive but I don't have the right Screwdriver