Please call our technical support team they would more than happy to help you. As it would be faster and easier way to clear all your queries. Thank you
best would be to consult our support, but let me give you few hints.
> vmware tools are not updated, can I reset root password and update them as a normal CentOS install or is it discouraged?
This is rather discouraged. This does not mean the VMware Tools isn’t working, but it may not have the latest features and fixes. They will be updated in next release of WHD.
> We are recording 100 / 120 tickets and 25MB files attached per week, with 10 techs. Will I run out of space soon?
Definitely not soon, but I recommend to monitor your diskspace as with any other server. It is not only database, but also database backup, which is over time filling the disk space.
> Is it possible to define an external location for attachments? (I would use our NAS)
You can do that by using external DB for all your WHD data.
> If in the future I will need to change to a different setup, a backup / restore of the database will be enough?
That depends on the type of change. If you decide to switch to a different DB, you might need to use migration tools. Plenty of options are available for different database systems.
> Do you suggest a particular configuration for our needs? Windows/Linux or MySQL/PostgreSQL?
PostgreSQL is most tuned for using with WHD, so embedded DB is recommend in general.
Hope that helps,