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Instead you should make use of the corret override file that is appropriate for your platform, and add values for (only) those options that you want to change.
On CentOS/RedHat, you need to create or modify /etc/sysconfig/nfdump
, on Debian/Ubuntu the correct file is /etc/default/nfdump
. Please note that this override file wins over the defaults that the init script sets.
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