calisun
> 1) I still don't understand Why to install in /opt and not ibay.
Potential security issues in the case of misconfiguration. Users can do things in ibays (change permisssions & so on), whereas they usually cannot do things in /opt as they don't have access to it.
There have been quite a few posts on this topic so go searching. The SiteMaker Howto on the Wiki came about probably due to this concern, see
http://wiki.contribs.org/SME_Site_MakerI personally don't see security issues if you install web apps to ibays, as long as you limit who has file sharing access to those ibays, so as to prevent inadvertant tampering, and you also know that those users are sensible and won't do things they should not be doing. Be particularly careful that files have correct (ie appropriate for security) ownership & permisssions, both user & group (I'm referring to the Linux file permissions here). Only a limited number of files & folders should have www ownership with write access (as required by the application in order to function), it's quite wrong & bad advice to see people setting whole folders/files to www:www 777
A reason for installing to ibays, would be to allow different groups of users to have access to the ibay to update their web site content, using say a VPN connection, eg for html based apps rather than Joomla.
As Joomla & other CMS's have their own built in content updating tools, there is no real need to put them in ibays, so there is a better security model if you put them in /opt.
> 2) .. if I install in /opt, people will only be able to get to it by typing mydomain.com/joomla??
It depends how you set up the redirect alias, refer also to some steps that happen when using SiteMaker contrib. You configure the alias the way you want it, so a straight domain name should be OK.
Note if you already have apps in an ibay, it's fairly easy to move them to /opt without any major dramas, just mv the files and edit a few config files in most cases.
> 3) You said: it IS a security risk if you have 2 or more Joomla sites running.
The risk that I see would be in not keeping your Joomla installs up to date with the latest bug free code. I'm not aware of security issues per se that relate to having multiple copies of a web app installed in different locations.
Perhaps the original poster of that comment can illuminate us.