Disk space usage with mdbox

[Alexandros Soumplis]

Hello,

I am using dovecot with mdbox+sis and I notice an ever increasing disk 
space usage since I converted mailboxes from Maildir to mdboxes. I have 
checked with a user and while it actually uses only 65K, his mdbox files 
on disk are more than 6G. The backup of his mailbox is just 64K. Any 
suggestions ?

Below are some relevant commands:

[root at mail ~]# doveadm quota get -u test
Quota name Type    Value 
Limit                                                          %
User quota STORAGE 10135 
31457280                                                          0
User quota MESSAGE   186 
-                                                          0

[root at mail ~]# du -k --max-depth=1 /mdboxes/test/
220    /mdboxes/test/mailboxes
6029348    /mdboxes/test/storage
6029592    /mdboxes/test/

[root at mail ~]# doveadm purge -u test
[root at mail ~]# du -k --max-depth=1 /mdboxes/test/
220    /mdboxes/test/mailboxes
6029348    /mdboxes/test/storage
6029592    /mdboxes/test/

[root at mail ~]# doveadm backup -u test  mdbox:/tmp/MDBOX_TEMP/
[root at mail ~]# du -k --max-depth=1 /tmp/MDBOX_TEMP/
16    /tmp/MDBOX_TEMP/mailboxes
65540    /tmp/MDBOX_TEMP/storage
65568    /tmp/MDBOX_TEMP/