I am having the same issue. I have just upgraded our hosting to a cluster and it now breaks with the error:
mkdir(): Input/Output error.
It turns out they use memcache. So the file sessions don't work.
I have found a dirty workaround that changes the sessions to work via the database, but it is very slow for me.
1. Create a file /application/config/concrete.php (if it doesn't exist).
2. Add this:
Changing it to memcache or memcached doesn't appear to work.
Anyone with any advice on getting it to work with memcache?
When it's other than database, it takes the
It's a pretty big step back in my opinion.