Hi,
Has anyone else come across performance issues running Drupal 7 on a virtual server?
We are currently running Drupal 7 on a virtual server with a single core processor and 3gb of ram (Red Hat 6).
Caching in Drupal and compression of javascript and css have been turned on but performance degrades considerably around the 50 user mark just hitting the homepage. Requests are taking about 15s to return. There is nothing remarkable about the homepage we have it is pretty much a static html page with no javascript/flash etc...
APC PHP caching was turned on and while it did improve the throughput and responsiveness around the 50 user mark (unauthenticated users) on reaching 100 users the site grinds to a halt and becomes unresponsive.
At the moment Drupal, Apache and the MySQL database all live on the same virtual server. We will be moving the database soon to its own dedicated machine where we are hoping to see better improvement. In saying that I would have expected slightly better performance that what we see given the current setup.
Is there a general rule of thumb out there for setting up Drupal 7 on a virtual server in terms of the numbers of cores and memory we should be giving Drupal 7?