replication hangs

[Laszlo Toth]

Hi,

I have 2 Dovecot servers (2.2.10) which are replicating each other. 
Replication works fine except for one user.

[root at dovecot2 ~]# doveadm -D sync -u username dovecot1
doveadm(root): Debug: Loading modules from directory: /usr/lib64/dovecot
doveadm(root): Debug: Module loaded: 
/usr/lib64/dovecot/lib15_notify_plugin.so
doveadm(root): Debug: Module loaded: 
/usr/lib64/dovecot/lib20_replication_plugin.so
doveadm(root): Debug: Loading modules from directory: 
/usr/lib64/dovecot/doveadm
doveadm(root): Debug: Skipping module doveadm_acl_plugin, because 
dlopen() failed: /usr/lib64/dovecot/doveadm/lib10_doveadm_acl_plugin.so: 
undefined symbol: acl_user_module (this is usually intentional, so just 
ignore this message)
doveadm(root): Debug: Skipping module doveadm_expire_plugin, because 
dlopen() failed: 
/usr/lib64/dovecot/doveadm/lib10_doveadm_expire_plugin.so: undefined 
symbol: expire_set_lookup (this is usually intentional, so just ignore 
this message)
doveadm(root): Debug: Skipping module doveadm_quota_plugin, because 
dlopen() failed: 
/usr/lib64/dovecot/doveadm/lib10_doveadm_quota_plugin.so: undefined 
symbol: quota_user_module (this is usually intentional, so just ignore 
this message)
doveadm(root): Debug: Module loaded: 
/usr/lib64/dovecot/doveadm/lib10_doveadm_sieve_plugin.so
doveadm(root): Debug: Skipping module doveadm_fts_plugin, because 
dlopen() failed: /usr/lib64/dovecot/doveadm/lib20_doveadm_fts_plugin.so: 
undefined symbol: fts_list_backend (this is usually intentional, so just 
ignore this message)
doveadm(username): Debug: Effective uid=489, gid=489, 
home=/data/mail/username
doveadm(username): Debug: fs: root=/data/mail/username, index=, 
indexpvt=, control=, inbox=, alt=
doveadm(username): Debug: Namespace : Using permissions from 
/data/mail/username: mode=0700 gid=default
dsync-local(username): Debug: brain M: in state=master_recv_handshake
dsync-local(username): Debug: brain M: out state=send_mailbox_tree 
changed=1
dsync-local(username): Debug: brain M: in state=send_mailbox_tree
dsync-local(username): Debug: brain M: out 
state=send_mailbox_tree_deletes changed=1
dsync-local(username): Debug: brain M: in state=send_mailbox_tree_deletes
dsync-local(username): Debug: brain M: out state=recv_mailbox_tree 
changed=1
dsync-local(username): Debug: brain M: in state=recv_mailbox_tree
dsync-local(username): Debug: brain M: out state=recv_mailbox_tree 
changed=0
dsync-local(username): Debug: brain M: in state=recv_mailbox_tree
dsync-local(username): Debug: brain M: out state=recv_mailbox_tree 
changed=0
dsync-local(username): Debug: brain M: in state=recv_mailbox_tree
dsync-local(username): Debug: brain M: out state=recv_mailbox_tree 
changed=0
dsync-local(username): Debug: brain M: in state=recv_mailbox_tree
dsync-local(username): Debug: brain M: out state=recv_mailbox_tree 
changed=0
dsync-local(username): Debug: brain M: in state=recv_mailbox_tree
dsync-local(username): Debug: brain M: out state=recv_mailbox_tree 
changed=0
dsync-local(username): Debug: brain M: in state=recv_mailbox_tree
dsync-local(username): Debug: brain M: out state=recv_mailbox_tree 
changed=0
dsync-local(username): Debug: brain M: in state=recv_mailbox_tree
dsync-local(username): Debug: brain M: out state=recv_mailbox_tree 
changed=0
dsync-local(username): Debug: brain M: in state=recv_mailbox_tree
dsync-local(username): Debug: brain M: out state=recv_mailbox_tree 
changed=0
dsync-local(username): Debug: brain M: in state=recv_mailbox_tree
dsync-local(username): Debug: brain M: out 
state=recv_mailbox_tree_deletes changed=1
dsync-local(username): Debug: brain M: in state=recv_mailbox_tree_deletes
dsync-local(username): Debug: brain M: out 
state=recv_mailbox_tree_deletes changed=0
dsync-local(username): Debug: brain M: in state=recv_mailbox_tree_deletes
dsync-local(username): Debug: brain M: out 
state=recv_mailbox_tree_deletes changed=0
dsync-local(username): Debug: brain M: in state=recv_mailbox_tree_deletes

...and it hangs. Both servers are CentOS 6.6 x64.

Replication status for the problematic user:
[root at deoveadm2 ~]# doveadm replicator status username
username priority fast sync full sync failed
username low      42:10:59  42:10:59  y

I tried to reindex the problematic mailbox, tried to restart both mail 
servers but the issue still here. I found no error messages in 
/var/log/maillog.
What should I try next?

Thanks,
Laszlo