We have a Magento ver. 18.104.22.168 setup with 4 fairly generous web servers (60GB RAM, 32 vCPU, 2x 320GB SSD storage) and a seperate admin server and (memcache, redis) cache servers.
However from time to time we're seeing php5-fpm spike and consume our CPU at 100% causing the front end website to be unusable for endusers.
This mostly happens during re-index or cache flush however even after the re-index is complete the CPU stays high and then the next reindex runs and tips the CPU over to 100%.
An idea is to offload re-index and cacheflush to be done by a pool of dedicated php5 servers away from the web servers, another approach is to review the configuration.Does anyone have the same issue or suggestions on how to prevent this? let me know if you need more info.