Does using IMAP web client make use of storage double times and waste storage?

[imax36581]

Dear Roundcube users
im new in this area and i have big question to answer,
If i use a IMAP webmail client, i store all of users inbox from my MDA to its database.is it true?
if yes if i have 500 users,each one 1 GB inbox so i should consider using half a terabyte for original mailbox location and another half a terabyte for storing the on imap webmail client?

thanks in advance

[SKaero]

RoundCube doesn't store the emails in its database it reads them directly from the mail server.

[alec]

There are two caching configuration options in Roundcube, if both are disabled (default) nothing is cached. If imap_cache is enabled, Roudcube will cache folder lists, metadata, counters, etc. If you enable messages_cache Roundcube will store messages data like headers (not all) and short (mostly text) message parts and message indexes (lists of message UIDs per folder, thread structures). Note that it stores only messages viewed by the user, so if there's 10k messages in a folder but user listed/viewed only 100, Roundcube will store data of only 100 messages.