Normally, dump transaction truncates the inactive portion of the log after copying it. Use with no_truncate to copy the log without truncating it.
no_truncate allows you to copy the transaction log after failure of the device that holds your data. It uses pointers in the sysdatabases and sysindexes tables to determine the physical location of the transaction log. Use no_truncate only if your transaction log is on a separate segment and your master database is accessible.
dump transaction mydb to "/dev/nrmt0" at REMOTE_BKP_SERVER with init, no_truncate, notify = "operator_console"