backupd - Cyrus IMAP documentation

       The Cyrus Team

       1993–2025, The Cyrus Team

3.10.2                                            Jun 27, 2025                                        BACKUPD(8)

NOTE:
          Cyrus Backups are experimental, incomplete, and deprecated as of 3.10.

       backupd  is  the  Cyrus  Backups  server.  It accepts Cyrus replication protocol commands on its standard
       input and responds on its standard output.  It MUST  be  invoked  by  master(8)  with  those  descriptors
       attached to a replication client connection, typically sync_client(8).

       backupd reads its configuration options out of the imapd.conf(5) file unless specified otherwise by -C.

       backupd  is  generally  configured to run on a dedicated backup server, containing backup storage, but no
       IMAP service or mailbox storage.

       You must configure at least one backuppartition.  User backups will be distributed among  the  configured
       partitions.  Note that there is no relationship between mailbox partitions and backuppartitions.

       If  the  directory  log/user  exists  under  the directory specified in the configdirectory configuration
       option, then backupd will create protocol telemetry  logs  for  sessions  authenticating  as  user.   The
       telemetry logs will be stored in the log/user directory with a filename of the backupd process-id.

backupd is commonly included in the SERVICES section of cyrus.conf(5) like so:

          SERVICES {
              backupdcmd="backupd"listen="csync"prefork=0
          }

       backupd - Cyrus IMAP documentation

       Cyrus Backups server process

-Cconfig-file
              Use the specified configuration file config-file rather than the default imapd.conf(5).

       -Uuses
              The  maximum  number  of times that the process should be used for new connections before shutting
              down.  The default is 250.

       -Ttimeout
              The number of seconds that the process will wait for a new connection before shutting down.   Note
              that a value of 0 (zero) will disable the timeout.  The default is 60.

       -D     Run external debugger specified in debug_command.

       -pssf Tell  backupd  that  an  external  layer  exists.  An SSF (security strength factor) of 1 means an
              integrity protection layer exists.  Any higher SSF implies some form of privacy protection.

imapd.conf(5), master(8), sync_client(8)

backupd [ -Cconfig-file ] [ -Uuses ] [ -Ttimeout ] [ -D ]
              [ -s ] [ -N ] [ -pssf ]