Here is the issue. We DO NOT want to use a 3rd party service, simply due to pricing.
We selected cs-cart in part of the built in newsletter features it has.
We have a VPS with 2gb of ram and a dedicated mysql server with 1GB , the site runs fine and rarely maxes out. with 500+ users.
Our main subscriber list is approx 150,000, we also have 3 others, dedicated for products, updates, and specials.
When we run our newsletter on the main list, it crashes our server because it sucks down 2 GB of ram, we have attempted to set the @ini_php to 1G, to limit the ram that script can use, however that is unsuccessful and it still drains our VPS of all the ram and our hosting company does an auto-reboot when it uses all the ram / maxes out. This can not be turned off on the hosting side.
What can we do to fix this issue? As stated, we dont want to pay or use any 3rd party service.
In my experience, 2GB is insufficient for running a reasonably acitiive commercial (versus hobby-type) store. We recommend a minimum of 6GB for our commercial clients but that includes allocation for mySQL. What is the connection between your DB server and your HTTP host? How many Apache threads are you running and how many active users (simultaneous)? I would guess (from the limited info available) that it is the DB connection where your bottleneck occurs (lack of memory means more buffering).
Just two cents from years of experience. I would also think that 1GB dedicated mySQL server is severely limited in memory. A good commercial config for a single VPS is:
6GB ram with 25-35% dedicated to file buffer allocation and 30% dedicated for mySQL allocation.