Looks like there is no enough information for litespeed to detect the version of Rails being used, and it defaults to Rails 2.3 branch of code.
If the Rails app involved is >2.3 release, you should set "RAILS_GEM_VERSION" variable in "config/environment.rb" explicitly for that application.
you need to check /usr/local/apache/logs/error_log to find out the reason why it is denied, then adjust configuration accordingly.
Try "Force reinstall" of 4.2, it might be fixed as we have adjusted default values to off.
There are many options,
http://www.litespeedtech.com/docs/webserver/config/security/#forceStrictOwnership
with 4.2, you can use
"DisableSymlinkOverride On" in httpd.conf.
or
"VhostRestrained On" in httpd.conf
The rtreport file is located at server level, if you run munin under one user account inside a cage, that user wont be able to access rtreport files. each cage has its own /tmp directory.
"DisableSymlinkOverride" does not allow change symbolic link related configuration via .htaccess
"VhostRestrained" does not allow linking to anywhere beyond user's home directory.
You need to check ip_conntrack limit, check output of 'dmesg', if the limit has been hit, you need to google it for solution.
Also, with your server, we recommend enabling "AIO" if you are serving tons of static files.
I do not think there is any change related to memory usage between lsapi 5.5 and 6.0 .
you have to test it on the same server with same PHP release.
to get back to 5.5, you can manually download php-litespeed package and over write *.c and *.h under php-xxxx/sapi/litespeed, the run make, copy...