Specifications
Escala Tower PL & S, E, T System Hardware
Chapter 3: External Storage and SAN Subsystems 73/116
9es3s1c3.doc
Rev 5.9
02/12/2003
5.4.11. Cache Memory
One of the most important components of a Symmetrix 8000 system is the cache memory. This cache
solution is field-proven, currently delivering over six million hours of continuous operation per week.
Cache boards are available in sizes of 1GB, 2GB, 4GB, and 8GB. These leading-edge memory boards
provide four independent areas on each board thereby increasing operations in each cache board.
Symmetrix 8430/8530 and 8730/8830 models have four cache slots to accommodate up to a maximum
of 32GB of cache memory per system.
All read and write operations transfer data to or from cache. All transfers between the host processor,
Channel Directors, and cache are achieved at electronic speeds that are a quantum leap faster than
transfers involving disk. The Symmetrix 8000 system’s intelligent use of cache contributes greatly to
this performance advantage: There are four internal buses (top high, top low, bottom high, and bottom
low), each has a 360MB per second bandwidth for a total internal processing bandwidth of 1440MB
per second.
5.4.12. Disk Drives
Symmetrix 8000 systems use advanced technology disk drives and disk controllers to enhance
Symmetrix capabilities. Microprocessors embedded in the controllers of each drive enable capabilities
such as advanced RAID protection to be offloaded from CPUs, disk directors and controllers. This
further enhances the performance of Symmetrix systems and also serves to make them more easily
compatible with a wide array of hardware and software platforms.
Symmetrix 8430/8530 and 8730/8830 systems support mixed configurations of up to 96, and 384
(respectively) 18GB, 36GB, 50GB, 73GB and 181GB disks drives (There are limitations to the
maximum capacity of the 8730 model. For more information, see "Symmetrix 8000 Family -
Configuration Summary".) This breadth of scalable capacity and configuration choices allows
Symmetrix systems to adapt to virtually any enterprise storage requirement.