Zimbra Mailbox Size Increase

Login to Zimbra:
[zimbra@smtp ~]# su - zimbra

Check existingMailbox size::
 [zimbra@smtp ~]$ postconf message_size_limit
message_size_limit = 10240000
** Looks 10M ..

We want to increase it 20M::
[zimbra@smtp ~]$ zmprov modifyConfig zimbraMtaMaxMessageSize 20480000

Reload Postfix::
[zimbra@smtp ~]$ postfix reload
/postfix-script: refreshing the Postfix mail system

Check Again::
[zimbra@smtpgw2 ~]$ postconf message_size_limit
message_size_limit = 20480000