Choose a budget RAID controller for file storage and archive?

Question

RAID

The task is to organize file storage and archive on an average budget PC configuration
(there is not enough budget for an adult server)
Config:
CPU - Intel Core i5-4590
MB - ASUS "B85-PLUS
RAM - 2x4GB DDR3
// controller
2 pcs. STLab A -550 (PCI-E x2) 4 ports
// files + archive
RAID 1
8pcs HDD -- 4TB Seagate ST4000NM0033
It is planned to cut 4 logical disks of 4TB each
// Debian 8 system
Separate disk without RAID on SATA interface
Questions:
1. Controller budget STLab A-550 (PCI-E x2)
www.sunrichtech.com.hk/ProductShow.aspx?Mid=1&pid=...
Are there any "pleasant surprises" during the installation and operation of this device?
2. It is planned to have 4 logical disks created in RAID. 4TB each
on 2 identical controllers:
1st controller 4 ports = RAID 1 ball 1 - 4TB and ball 2 - 4TB)
2nd controller 4 ports = RAID 1 archive 1 - 4TB and archive 2 - 4TB
connect samba balls for users, is this action possible?

Answer 1

The most budget mdadm controller