Purging old email files from Cyrus-IMAPD v.3.0.9 on FreeBSD-12.0

[James B. Byrne]

We converted from v.2.0.? to v.3.0.? last year.  We accepted the
default settings for delete/expunge.  Now we have suspicions that
deleted and expunged email is not actually being deleted from the file
system and the space recovered.

Looking at the man page for cyr_expire I see this:

       The expiration of messages is controlled by the
       /vendor/cmu/cyrus-imapd/expire mailbox annotation
       which specifies the age (in days) of messages in
       the given mailbox that should be deleted. A value
       of 0 means that no expiration is to be performed
       on that mailbox.

       The value of the /vendor/cmu/cyrus-imapd/expire
       annotation is inherited by all children of the mailbox
       on which it is set, so an entire mailbox tree can be
       configured by setting a single annotation on the root of
       that tree.  If a mailbox does not have a
       /vendor/cmu/cyrus-imapd/expire annotation set on it
       (or does not inherit one), then no messages are expired
       from the mailbox.

       The annotation can be examined using the info command
       of cyradm(8), and modified using the mboxconfig and setinfo
       commands of cyradm(8).


The following is a representative user mailbox on our server:


 info user/usrname
{user/usrname}:
  private:
    check: NIL
    checkperiod: NIL
    comment: NIL
    sort: NIL
    specialuse: NIL
    thread: NIL
    expire: NIL
    news2mail: NIL
    sieve: NIL
    squat: NIL
  shared:
    check: NIL
    checkperiod: NIL
    comment: NIL
    sort: NIL
    specialuse: NIL
    thread: NIL
    annotsize: 0
    duplicatedeliver: false
    expire: NIL
    lastpop: NIL
    lastupdate: 15-May-2019 04:16:08 -0400
    news2mail: NIL
    partition: default
    pop3newuidl: true
    pop3showafter: NIL
    sharedseen: false
    sieve: NIL
    size: 2105288
    squat: NIL
    synccrcs: 1325519995 0
    uniqueid: 6bcd81f457596d11


Our cyrus.conf file has this:

  delprune      cmd="cyr_expire -D 180d -E 3d -X 180d" at=0400

My question is:  When are message files actually removed from our
server's the file system and the space recovered?  Is there a setting
or utility option required to perform this action / accomplish this
result?  How does one verify the removal?

-- 
***          e-Mail is NOT a SECURE channel          ***
        Do NOT transmit sensitive data via e-Mail
 Do NOT open attachments nor follow links sent by e-Mail

James B. Byrne                mailto:ByrneJB at Harte-Lyne.ca
Harte & Lyne Limited          http://www.harte-lyne.ca
9 Brockley Drive              vox: +1 905 561 1241
Hamilton, Ontario             fax: +1 905 561 0757
Canada  L8E 3C3