Hi Gonzalo,
The OMERO virtual appliance (as described here
http://www.openmicroscopy.org/site/supp ... iance.html) is meant for evaluation purposes and as such the team can't guarantee it will perform under heavy load. There is a set of limiting factors (limited drive space, running in VirtualBox etc.) for using it in production setup.
The default credentials are provided here -
http://www.openmicroscopy.org/site/supp ... redentials. Changing the database password would require logging in as root and using the
psql command to change the password for the
omero user.
With kind regards,
Blazej