Wednesday, 30 July 2014

ORA-00445: background process "m001" did not start after 120 seconds ---ORA-00445: background process "J003" did not start after 120 seconds

ORA-00445: background process "m001" did not start after 120 seconds 
    Incident details in: /app/u01/app/oracle/diag/rdbms/incident/incdir_3721/db1_mmon_7417_i3721.trc 
    ERROR: Unable to normalize symbol name for the following short stack (at offset 2): 
    Tue Jun 21 03:03:06 2011 
    ORA-00445: background process "J003" did not start after 120 seconds 
    Waited for process W002 to initialize for 60 seconds 
    The system appears to be running very slowly and defunct processes can appear. 
    REDHAT 5 kernel 2.6.18-194.el5 #1 SMP Tue Mar 16 
    Oracle Single Instance 
    IBM: Linux on System z 
    Recent linux kernels have a feature called Address Space Layout Randomization (ASLR). 
    ASLR  is a feature that is activated by default on some of the newer linux distributions. 
    It is designed to load shared memory objects in random addresses. 
    In Oracle, multiple processes map a shared memory object at the same address across the processes. 
    With ASLR turned on Oracle cannot guarantee the availability of this shared memory address. 
    This conflict in the address space means that a process trying to attach a shared memory object to a specific address may not be able to do so, resulting in a failure in shmat subroutine. 
    However, on subsequent retry (using a new process) the shared memory attachment may work. 
    The result is a random set of failures 
    It should be noted that this problem has only been positively diagnosed in Redhat 5 and Oracle 
    It is also likely, as per unpublished BUG:8527473,  that this issue will reproduce running on Generic Linux platforms running  any Oracle 11.2.0.x. on Redhat/OEL kernels which have ASLR.  
    ASLR also exists in SLES10 and SLES 11 kernels and by default ASLR is turned on, however, to date not problem has been seen on SuSE. 
    You can verify whether ASLR is being used as follows: 
     # /sbin/sysctl -a | grep randomize 
    kernel.randomize_va_space = 1 
    If the parameter is set to any value other than 0 then ASLR is in use. 
    On Redhat 5 to permanently disable ASLR. 
    add/modify this parameter in /etc/sysctl.conf 
    You need to reboot for kernel.exec-shield parameter to take effect.  
    Note that both kernel parameters are required for ASLR to be switched off.