this night after finished backup there was followiing issue.

here is the log excerpt:

this was last account added to incremental backup
Code:
2014-05-22 01:00:20,511 INFO  [qtp679447471-207811:https://127.0.0.1:7071/service/admin/soap/BackupRequest] [name=a.ar....@ta...on.it;mid=14;ip=127.0.0.1;ua=zmbackup/8.0.6_GA_5922;] backup - Account a.ar....@ta...on.it in backup set incr-20140521.230019.945: All pending file IO completed (0 out of 0)
2014-05-22 01:00:20,697 INFO  [qtp679447471-207811:https://127.0.0.1:7071/service/admin/soap/BackupRequest] [ip=127.0.0.1;ua=zmbackup/8.0.6_GA_5922;] redolog - waiting for FileLogWriter.FsyncThread-1400626815120 to finish.
the second line is the issue: waiting for FileLogWriter.FsyncThread-1400626815120 to finish.
This task never ever come to an end.

After 26 minutes the first crash



Code:
2014-05-22 01:26:29,367 ERROR [qtp679447471-207811:https://192.168.222.14:443/Microsoft-Server-ActiveSync?User=e.v...@ta...on.it&DeviceId=ApplDNPHCVWADTC0&DeviceType=iPhone&Cmd=Ping] [ip=79.17.133.136;] mailbox - Failed to lock mailbox
Lock Owner - MailboxPurge prio=5 id=51 state=WAITING
        at sun.misc.Unsafe.park(Native Method)
        at java.util.concurrent.locks.LockSupport.park(LockSupport.java:186)
        at java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(AbstractQueuedSynchronizer.java:834)
        at java.util.concurrent.locks.AbstractQueuedSynchronizer.doAcquireSharedInterruptibly(AbstractQueuedSynchronizer.java:994)
        at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireSharedInterruptibly(AbstractQueuedSynchronizer.java:1303)
        at java.util.concurrent.locks.ReentrantReadWriteLock$ReadLock.lockInterruptibly(ReentrantReadWriteLock.java:776)
        at com.zimbra.cs.redolog.RedoLogManager.logOnly(RedoLogManager.java:428)
        at com.zimbra.cs.redolog.RedoLogManager.log(RedoLogManager.java:379)
        at com.zimbra.cs.redolog.op.RedoableOp.log(RedoableOp.java:121)
        at com.zimbra.cs.mailbox.Mailbox.endTransaction(Mailbox.java:8585)
        at com.zimbra.cs.mailbox.Mailbox.purgeMessages(Mailbox.java:8051)
        at com.zimbra.cs.mailbox.PurgeThread.run(PurgeThread.java:155)

com.zimbra.cs.mailbox.MailboxLock$LockFailedException: timeout
        at com.zimbra.cs.mailbox.MailboxLock.lock(MailboxLock.java:58)
        at com.zimbra.cs.mailbox.Mailbox.beginTrackingSync(Mailbox.java:3182)
        at com.zimbra.zimbrasync.ZimbraSyncServlet.processPostRequest(ZimbraSyncServlet.java:475)
        at com.zimbra.zimbrasync.ZimbraSyncServlet.doPost(ZimbraSyncServlet.java:431)
By now on, java was unable to lock mailbox anymore, until I restarted mailboxd at 8:29



Should I raise any parameter following wiki https://wiki.zimbra.com/wiki/Perform...ge_Deployments ?
This is a very small installation, with a few accounts