Question about backup files under /var/imap/db

[Daniel Qian]

In the /var/imap/db directory of my email server I noticed several backup 
files:
__db.001  __db.002  __db.003  __db.004  __db.005  log.0000000001 mailbox.dump
I figure I may use these files to restore messages in mailboxes. But I 
couldn't find any documentation as to how these files are created and how I 
could use them to restore mailboxes. Anyone can give me some ideas how they 
work or point me to some resources where I can get to know how?

 
Best Regards,
Daniel Qian


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Best Regards,
Daniel Qian