22 High Performance Parallel I/O
storage subsystem integrates Scalable Storage Units (SSU) that each has two
industry-standard x86 Embedded Server Modules (ESMs) based on the Intel
Sandybridge
TM
processors. The ESMs connect directly through a common mid-
plane to all drives in the SSU and share a redundant high-speed interconnect
across the midplane for failover services. The ESMs run an industry-standard
Linux distribution and each module has its own dedicated CPU, memory,
network, and storage connectivity.
Each SSU contains eighty-two, 2-TB, 7200-RPM NL-SAS disk drives
housed in two trays. Eighty data drives are configured in eight RAID 6 (8+2)
arrays resulting in 64 usable data drives. The other two drives in the SSU are
global hot spares. Each SSU ...