This is my method - something is wrong with it, looking for help;
1. D6 version of site work fine at mydomain.com
2. D7 dev version of site works fine at new.mydomain.com (a folder under root of mydomain.com - mydomain.com/new ).
To go live with new D7 site, I thought I would do this so as not to have to FTP:
A. Put both sites into maintenance mode.
B. Copied the D6 site files into a folder I created in root of mydomain.com called _BACKUP
C. Copied the D7 site files from the 'new' folder into the root of mydomain.com.
Initially I see the D7 "site under maintenance" at mydomain.com. But when I try to login mydomain.com/user I get 500 error and "Fatal error: Allowed memory size of 33554432 bytes exhausted (tried to allocate 20 bytes) in /home/[user]/public_html/includes/cache.inc on line 447"
In the past I have made new versions of sites live by deleting old files in root of mydomain.com and FTPing new site files from local to root of mydomain.com. But I thought the above method might be better as it it faster to revert to old site is something goes wrong.
Any thoughts on what what is wrong with this method? Wondering if the D6 files still sitting in _BACKUP folder somehow cause a problem.