The Sun Fire E25K (codenamed Amazon 25) is an enterprise-class server computer from Sun Microsystems. Announced in February 2004, the machine could be described as an upgraded Sun Fire 15K as the base cabinets are identical with the only difference between them being the processor boards installed. It reached end-of-life in January, 2009, and was superseded by the Sun SPARC Enterprise M9000 server.
The E25K supports up to 72 dual-core UltraSPARC IV+ processors (up to 1.95 GHz) installed across 18 system boards. Whereas in the 15K there is the possibility to use slots of an additional crossbar switch to plug in extra 2-CPU boards to extend the computational power at the cost of I/O capacity, this possibility is not offered for the E25K system. Overall system bandwidth is claimed as up to 172.8 GB/s aggregate, up to 115.2 GB/s peak, and up to 43.2 GB/s sustained. For overall I/O bandwidth, up to 35.8-GB/s sustained. Up to 64 GB of RAM per board is possible with a maximum of 1.15 TB of RAM for a single domain. Up to 72 hot swappable PCI-X I/O slots; 54 slots are 90 MHz, 18 slots are 33 MHz. It also supports 10/100 BaseT Ethernet, Gigabit Ethernet, UltraSCSI (LVD and HVD), ATM, FC-AL, HSI and SCI.
The system can be divided into a maximum of 18 secure independent domains (one domain per system board), each of which is a separate machine with its own filesystems, root password and can run different versions of Solaris. Administrators can dynamically change the assignment of RAM and processors to the different domains to meet changes in business needs. In addition, the E25K contains two system controllers (duplicated for redundancy), which are Solaris systems used to manage the 25K and perform tasks such as booting and shutting down domains and assigning CPUs and RAM to domains. The E25K contains minimal storage in itself (only system controller boot disks); it is connected to a separate enterprise storage system.