After putting my NAS in a separate storage VLAN I noticed that my network throughput was slow to and from the NAS. The throughput of a simple file copy from a windows laptop (wired at 1 GbE) to a SMB share on the NAS was only 17,7 MB. The Windows laptop was on a different VLAN then the NAS.
After some troubleshooting I noticed that the throughput within the VLAN was okay (120 MB/s on a 1 GbE network). The routing between the VLANs is done by Ubiquiti EdgeRouter Lite. I investigated the Ubiquiti EdgeRouter settings by using SSH and noticed that VLAN forwarding for IPv4 was disabled by using the following command:
ubnt@ubnt:~$ show ubnt offload IP offload module : loaded IPv4 forwarding: enabled vlan : disabled pppoe : disabled gre : disabled IPv6 forwarding: disabled vlan : disabled pppoe : disabled IPSec offload module: loaded Traffic Analysis : export : disabled dpi : disabled version : 1.354
The following commands enable VLAN forwarding for IPv4 and save the setting:
ubnt@ubnt:~$ configure  ubnt@ubnt:# set system offload ipv4 vlan enable  ubnt@ubnt: commit  ubnt@ubnt:# save Saving configuration to '/config/config.boot' ... Done 
This config change can be done without a reboot of the router. After making this change the network throughput was as expected. So make sure to do some tests and check VLAN offloading in the Ubiquiti EdgeRouter (it’s default disabled).