[rdiff-backup-users] rdiff-backup dies with ENOMEM due to requesting enormous amounts of memory

[Jeff White]

I'm trying to get rdiff-backup working for the first time across SSH 
(with sudo) on two CentOS 7 hosts.  I'm getting the following crash:

$ sudo rdiff-backup --restrict-read-only / -v5 --remote-schema 'ssh -l 
rdiff -i /home/rdiff/.ssh/id_rsa -t -t %s "sudo /usr/bin/rdiff-backup 
--server"' bacula-p1n01::/ /dumps/bacula-p1n01/
Thu Jun  9 15:34:42 2016  Using rdiff-backup version 1.2.8
Thu Jun  9 15:34:42 2016  Executing ssh -l rdiff -i 
/home/rdiff/.ssh/id_rsa -t -t bacula-p1n01 "sudo /usr/bin/rdiff-backup 
--server"
Thu Jun  9 15:34:42 2016  Client sending (0): ConnectionRequest: 
Globals.get with 1 arguments
Thu Jun  9 15:34:42 2016  Client sending (0): 'version'
Connection to bacula-p1n01 closed.
Thu Jun  9 15:34:43 2016  Exception '' raised of class '<type 
'exceptions.MemoryError'>':
  File "/usr/lib64/python2.7/site-packages/rdiff_backup/Main.py", line 
304, in error_check_Main
    try: Main(arglist)
  File "/usr/lib64/python2.7/site-packages/rdiff_backup/Main.py", line 
321, in Main
    rps = map(SetConnections.cmdpair2rp, cmdpairs)
  File 
"/usr/lib64/python2.7/site-packages/rdiff_backup/SetConnections.py", 
line 76, in cmdpair2rp
    if cmd: conn = init_connection(cmd)
  File 
"/usr/lib64/python2.7/site-packages/rdiff_backup/SetConnections.py", 
line 150, in init_connection
    check_connection_version(conn, remote_cmd)
  File 
"/usr/lib64/python2.7/site-packages/rdiff_backup/SetConnections.py", 
line 158, in check_connection_version
    try: remote_version = conn.Globals.get('version')
  File "/usr/lib64/python2.7/site-packages/rdiff_backup/connection.py", 
line 450, in __call__
    return apply(self.connection.reval, (self.name,) + args)
  File "/usr/lib64/python2.7/site-packages/rdiff_backup/connection.py", 
line 368, in reval
    result = self.get_response(req_num)
  File "/usr/lib64/python2.7/site-packages/rdiff_backup/connection.py", 
line 315, in get_response
    try: req_num, object = self._get()
  File "/usr/lib64/python2.7/site-packages/rdiff_backup/connection.py", 
line 240, in _get
    data = self._read(length)
  File "/usr/lib64/python2.7/site-packages/rdiff_backup/connection.py", 
line 210, in _read
    try: return self.inpipe.read(length)

Traceback (most recent call last):
  File "/usr/bin/rdiff-backup", line 30, in <module>
    rdiff_backup.Main.error_check_Main(sys.argv[1:])
  File "/usr/lib64/python2.7/site-packages/rdiff_backup/Main.py", line 
304, in error_check_Main
    try: Main(arglist)
  File "/usr/lib64/python2.7/site-packages/rdiff_backup/Main.py", line 
321, in Main
    rps = map(SetConnections.cmdpair2rp, cmdpairs)
  File 
"/usr/lib64/python2.7/site-packages/rdiff_backup/SetConnections.py", 
line 76, in cmdpair2rp
    if cmd: conn = init_connection(cmd)
  File 
"/usr/lib64/python2.7/site-packages/rdiff_backup/SetConnections.py", 
line 150, in init_connection
    check_connection_version(conn, remote_cmd)
  File 
"/usr/lib64/python2.7/site-packages/rdiff_backup/SetConnections.py", 
line 158, in check_connection_version
    try: remote_version = conn.Globals.get('version')
  File "/usr/lib64/python2.7/site-packages/rdiff_backup/connection.py", 
line 450, in __call__
    return apply(self.connection.reval, (self.name,) + args)
  File "/usr/lib64/python2.7/site-packages/rdiff_backup/connection.py", 
line 368, in reval
    result = self.get_response(req_num)
  File "/usr/lib64/python2.7/site-packages/rdiff_backup/connection.py", 
line 315, in get_response
    try: req_num, object = self._get()
  File "/usr/lib64/python2.7/site-packages/rdiff_backup/connection.py", 
line 240, in _get
    data = self._read(length)
  File "/usr/lib64/python2.7/site-packages/rdiff_backup/connection.py", 
line 210, in _read
    try: return self.inpipe.read(length)
MemoryError


On that host when I strace the process I see:

[pid 11602] mmap(NULL, 18118029061677056, PROT_READ|PROT_WRITE, 
MAP_PRIVATE|MAP_ANONYMOUS, -1, 0 <unfinished ...>
...
[pid 11602] <... mmap resumed> )        = -1 ENOMEM (Cannot allocate memory)


... am I mistaken or is rdiff-backup requesting a ridiculous amount of 
memory?  Why would it do that?

--
Jeff White
HPC Systems Engineer
Information Technology Services - WSU