null

Search is a good lead. I haven't used Elastica, but if it's similar to the solr module, it will use queued jobs for periodic indexing

null

yeah, along those lines, start removing modules until you find the one that breaks it

null

You'd have to specifically configure them, in your YML

null

are you using any other cache engines, like memcached or anything like that?

null

then the usual dev/build flush= to ensure it's cleared

null

rm -rf your local cache. Should be somewhere like /tmp/silverstripe-cache-

null

I have seen that error before, but it's been a while. Can't remember the cause