partition usb to boot from and store movies on other partition, possible??

[Kronus]

Hello all,

I know this is an rather old post but I'm also new, new to this community and very very new to Linux.
English is also not my native language so forgive me my dumbness and incorrect grammar and please do correct me if I'm wrong.

If I get it right then it is not possible (or wise) to boot from SD (of course) and have the XBMC on a HDD?
I'm just wondering what is the most smooth and fast setup for XBMC. The HDD I want to use is for homemade holiday-movies and -pictures (and tv-recordings through minidlna (I don't want to get stuck with tweaking a tv-card on the RPi)).
What is the most suitable format for this HDD? NFS? EXT4?

Second I want to install something like domoticz (or HomeGenie). Better install it on a different partition of the HDD or use an other HDD?

Due my lack of Linux knowledge the wiki also sound like hocus pocus to me.

I hope you can point me out/advise me, THX.


Software
XBian version: 20150114-2
XBMC/Kodi version: 13.2 Gotham
Overclock settings: default

Hardware
Device type and model (e.g. Raspberry Pi Model A/B 256/512 MB, CuBox-i i4Pro, ...): RPi Model B
Power supply rating: 5V 2A through Trust HU-5870V powered 7-port USB hub
SD card size and make/type: 4 GB Integral class 10
Network (Ethernet or wireless): Ethernet
Connected devices (TV, USB, network storage, ...): TV, Bluetooth dongle, Z-stick and depending on answer(s) 1 or 2 selfpowerd HDD

Log files
Link to logfile(s):

Problem description:
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How to reproduce:
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