[ovirt-users] Can I reduce the Java heap size of engine-backup???

[John Florian]

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?

-- 
John Florian