What IMAP server do you use? I use Linux filesystem quotas, and Dovecot is configured to look at them. I did not have to do anything to make quota display work in Roundcube, I assume that Roundcube queries Dovecot which reads them from the filesystem. It works perfectly in my system.
Thanks SKaero and ABerglund,
Coding the plugin would be the last option
I use Courier IMAP and since squirrelmail had the plugin to display filesystem quota, I did not even try to see the quota configs in Courier.
I will check if Courier can read and report filesystem quotas. I am puzzled however, if the Dovecot can read filesystem quota out of the box. I thought it will read and report size of ~/Maildir only.
Anyway, if SKaero is right then it means that roundcube does not yet have an independent plugin which can check and report the filesystem quota, it has to rely on the IMAP server for the quota.
Thanks again.