I have a hybrid cluster (3 nodes) with 2x1,9TB SSDs and 10x4TB NL-SAS drives. Is it possible to replace all the disk in the cluster to make it all-flash?
It is possible, a client that I have requested that change ... design a work plan with the steps ... however I strongly recommend opening a case with support ... Nothing is better than having a validation by support. Officially there is no procedure. But it is possible.
Please involve the Hardware Vendor to confirm if the procedure is possible on the Platform concerned and the configuration is approved before proceeding.
An additional consideration in a mixed cluster is to verify the number of All Flash nodes as there is a minimum requirement.