Hi,  Thank you for your question on EMC forum. Single SP module will have a cache protection module configured. All data available in cache of SPA will be mirrored to cache protection module for redundancy.  So write cache is enabled even with single SP system.  Write cache feature is to store data in it and send ACK to host that write has be completed on VNXe. After this, cache module will commit the data on drives.  If there is an event of power failure, cache protection module (Mirrored) will copy the cache data to a non-volatile storage (SSD/Flash).  Note: In normal circumstances, Flash/SSD will not be used for caching.  Regards, Swapnil
I think I know the right answer to this question, but I thought I would confirm and at the same time have the information documented in the community.    With a VNXe 3150 configured with a single controller, does the array have write cache enabled?  It is my understanding that it does and everything is stored on a internal flash disk to prevent data loss.  However, are the IOs first written to memory cache and then moved down to flash disk and then written back to actual disk?    If someone has a good explanation of this process, would you please share it with the community?  Thank you.
VNXe 3150 Single Controller & Write Cache