Good post by George Crump (thank you)
Server SSDs have been primarily focused on providing boot drives for SAN attached servers, for memory extension solutions when paging out virtual memory or for caching hard disks. The primary reasons for these limited use cases are concerns over reliability, availability and capacity. To address these implementation issues IBM and SMART Storage Systems joined forces to create the eXFlash solution. Designed for System X Servers, the IBM eXFlash solution is a truly unique server flash solution that overcomes the shortcomings of other server SSDs while offering superb performance. The result should be a much broader application of server based SSD technology.
Read on here