I have a client site that was updated to ee2 (2.5.0) about 15 months ago. Its at http://www.smart-publications.com. The host both after and before that upgrade is yourhost.com. Everything worked fine. I updated them to 2.6.1, and updated all the add-ons that needed an update, about 10 days ago. Deployed the updates and within 15 minutes the server came down due to runaway memory usage. After working with the host and trying a few more times, no change.
We run a Rackspace cloud sites server for some client hosting, so I setup a site there and deployed the files. Using the testing URL that Rackspace provides, the site seemed fine. I opened the site in 8 tabs with auto reload on and the memory didn't go nuts. So I pointed the A record to this server for the time being and that is where the site is running now.
I figured that Yourhost may not have servers optimized for EE so I recommended to the client setting up a VPS on Liquidweb, which I used for years with EE1 and 2 sites before Rackspace. We did that, and I deployed the site there and, using a spare domain name I own, set the site up for that. Opening several tabs with the auto reload running sent the memory on the server out of control.
I thought maybe it was a 2.6.1 issue, or one of the add ons that I had updated, so I blew away the site and redeployed it using the original 2.5.0 version before I had done any of the upgrades. Same problem.
Can anyone help be figure out what the hell is going on? I've never seen anything like this.