On Tue, Dec 29, 2015 at 12:51 AM, John Florian <jflorian@doubledog.org> wrote:
I'm trying to run the engine-backup script via a Bacula job using the RunScript option so that the engine-backup dumps its output someplace where Bacula will collect it once engine-backup finishes. However the job is failing and with enough digging I eventually learned the script was writing the following in /tmp/hs_err_pid5789.log:
# # There is insufficient memory for the Java Runtime Environment to continue. # Native memory allocation (mmap) failed to map 2555904 bytes for committing reserved memory. # Possible reasons: # The system is out of physical RAM or swap space # In 32 bit mode, the process size limit was hit # Possible solutions: # Reduce memory load on the system # Increase physical memory or swap space # Check if swap backing store is full # Use 64 bit Java on a 64 bit OS # Decrease Java heap size (-Xmx/-Xms) # Decrease number of Java threads # Decrease Java thread stack sizes (-Xss) # Set larger code cache with -XX:ReservedCodeCacheSize= # This output file may be truncated or incomplete. # # Out of Memory Error (os_linux.cpp:2627), pid=5789, tid=140709998221056 # # JRE version: (8.0_65-b17) (build ) # Java VM: OpenJDK 64-Bit Server VM (25.65-b01 mixed mode linux-amd64 compressed oops) # Failed to write core dump. Core dumps have been disabled. To enable core dumping, try "ulimit -c unlimited" before starting Java again #
So is there any good way to reduce the Java heap size? I mean I know what -Xmx does, but where might I try setting it, ideally so that it affects the engine-backup only? Any idea of good setting for a very small environment with a dozen VMs?
engine-backup does not directly call nor need java. AFAICS it only calls it indirectly as part of some other initialization by running java-home [1], which is a script that decides what JAVA_HOME to use for the engine. This script only runs 'java -version', which imo should not need that much memory. Perhaps there is something else I do not fully understand, such as bacula severely limiting available resources for the process it runs, or something like that. If you only want to debug it, and not as a recommended final solution, you can create a script [2] which only outputs the needed java home. Simply run [1] and make [2] echo the same thing. If [2] exists, [1] will only run it and nothing else, as you can see inside it. I do not think this will work - quite likely engine-backup will fail shortly later, if indeed it gets access to so little memory. Please report back. Thanks and good luck, [1] /usr/share/ovirt-engine/bin/java-home [2] /usr/share/ovirt-engine/bin/java-home.local -- Didi