Accessing your Quickbooks file through a NAS (Network Attached Storage) device is no longer supported by Intuit. They did support storing the QB file on a NAS while running Database Helper on a Windows or Linux host for a few years. This is no longer true for both single and multi-user configurations.
You are able to backup your QB file to a NAS device. However, you will no longer receive support if you attempt to run the QuickBooks application from a file stored on a NAS or via VPN.
Uplevel is aware that several of our partners have had success serving QB files from NAS and accessing their files via VPN. We also know of partners who have had bad experiences serving QB files from NAS and via VPN. This is not under our control, nor something that we can tune on our end to improve performance.
Here is a list of the supported and not supported storage and networks from the current Intuit QuickBooks Website:
We have heard from partners that they have had success serving QB files from Linux Servers. Here is a forum that discusses the prospect. This link is only for reference, Uplevel can not help support your QuickBooks installations.
Serving QB files from a yum/rpm Linux Server: