su vs sudo in init script

[Tom Chiverton]

I've just installed the latest CouchDb (from source, using EPEL's 
erlang) on the latest Amazon Linux, and although it starts up, the 
'verify your installation' tests from Futon do not complete, and errors 
like this:

    [Fri, 25 Sep 2015 15:14:05 GMT] [error] [<0.20.0>] 
{error_report,<0.9.0>,
                                 {<0.20.0>,std_error,
                                  "File operation error: eacces. 
Target: ./couch_os_daemons.beam. Function: get_file. Process: 
code_server."}}

are logged.
If I alter the init script run_command() to be
      if sudo -i -u $COUCHDB_USER $command ; then
instead of
      if su ...
then everything goes smoothly.

Does anyone know what I might have done wrong ? To add the user I did:
sudo adduser -r --home /usr/local/var/lib/couchdb -M --shell /bin/bash 
--comment "CouchDB Administrator" couchdb
sudo chown -R couchdb:couchdb /usr/local/etc/couchdb
sudo chown -R couchdb:couchdb /usr/local/var/lib/couchdb
sudo chown -R couchdb:couchdb /usr/local/var/log/couchdb
sudo chown -R couchdb:couchdb /usr/local/var/run/couchdb
sudo chown -R couchdb:couchdb /usr/local/lib/couchdb
sudo chmod 0770 /usr/local/etc/couchdb
sudo chmod 0770 /usr/local/var/lib/couchdb
sudo chmod 0770 /usr/local/var/log/couchdb
sudo chmod 0770 /usr/local/var/run/couchdb
--
*Tom Chiverton*
Lead Developer
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