[wp-hackers] Multisite memory issue

[Jesse Friedman]

I have a rather large multisite network powering close to 500 sites. We
don't get a lot of traffic, maybe 250,000 uniques a month.

Last year we had 100 sites running on a well known WordPress only hosting
company that uses varnish cache.  We've grown by 400 sites in the last 3
months and have immediately experienced major memory problems.

We upgraded our hosting plan and are now running a bare metal box, with
master / slave database replication.  However we are still seeing some
memory issues. It is not as bad as it was, but here are some specs and
symptoms.

Symptoms:

   - White screens (not of death), if you simply refresh the page loads.
   This happens on a site level and occurs about 50 times a day
   - On a network level sites.php or users.php show white screens for users
   that frequent the network. The more sites I visit the more likely I will
   get the white screen. However if I create a brand new super admin user I
   can browse the network admin just fine
   - Probably unrelated, the plugins section is no longer identifying
   plugin upgrade needs. In other words WordPress SEO needs an upgrade now but
   it isn't telling me or giving me the option to auto update
   - The site and user count in the dashboard is way off. Now most of these
   sites were generated by moving them in from another multisite manually
   through the database

PHP Fatal error: Allowed memory size of 134217728 bytes exhausted (tried to
allocate 44484 bytes) in /nas/wp/www/sites/__/wp-content/object-cache.php
on line 196, referer: url of site page

PHP Fatal error: Allowed memory size of 268435456 bytes exhausted (tried to
allocate 317441 bytes) in
/nas/wp/www/sites/__/wp-admin/includes/class-wp-ms-sites-list-table.php on
line 282

PHP Fatal error: Allowed memory size of 134217728 bytes exhausted (tried to
allocate 38780 bytes) in /nas/wp/www/sites/__/wp-content/object-cache.php
on line 196, referer: url of site page


Specs
We have hundreds of in house made themes and 1 in house framework plugin.
Network Activated Plugins:

   - Akismet
   - Blog Copier
   - Breadcrumb NavXT
   - Gravity Forms
   - Jetpack
   - Redirection
   - Simple 301 Redirects
   - WordPress Importer
   - WordPress MU Domain Mapping
   - WordPress SEO
   - WP-Paginate
   - WP Mobile Detect

443 themes
288 users


The hosting provider said it was the shear size of our network that
required us to upgrade the hardware. Now that we are on this super robust
system, they are convinced its a plugin or theme causing a memory problem.

*HELP PLEASE! :*)

   - Has anyone had any luck tracking a memory issue through hundreds of
   sites, using network activated plugins but hundreds of different themes?
   - Right now I feel like the memory issue could be either the size of our
   network or something in our code, but i have no idea how to find the
   problem.
      - I have duplicated the network into a staging environment and we
      have no issues there but there is also no traffic. I believe that I need
      traffic to the network to be able to duplicate the problem
      - I can not turn off any of the plugins without breaking the network
      - I can not turn off any themes without disabling client sites


-- 
thanks

*jesse friedman*
jes.se.com
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