IBM 440 manual Rack installation

(%)	400 -		File/Print Serving
			Environment
Performance
	300 -
	200 -		118	116	114
	100 -	100
Relative
		1	2	3	4
			Number of
			Processors

400 -		Database/Application
		Environment
300 -			230	280
		175
200 -
100 -	100
	1	2	3	4
		Number of
		Processors

Figure 3-12 Effect of adding processors under file/print and application environments

SMP will not provide a linear improvement in processing power as additional processors are added. You might achieve a 70-90% performance increase from the second processor, but each additional processor after the second will provide a diminishing return on investment as other system bottlenecks come into play.

For more information regarding multiprocessor systems and performance tuning xSeries servers, refer to the redbook Tuning IBM ^xSeries Servers for Performance, SG24-5287.

For performances results of four-way and eight-way x440s running SAP and TPC-C benchmarks, see:

http://www.pc.ibm.com/ww/eserver/xseries/benchmarks/series.html

3.7 Rack installation

The x440 is 4U in height and is intended for use as a rack-drawer server. Due to power distribution considerations, it is recommended that no more than eight 4U x440 chassis be installed in a single 42U rack, leaving 10U available for RXE-100 Remote I/O enclosures, disk or tape storage, or other devices.

The x440 is 27.5" deep, and is designed to be installed in a 19-inch rack cabinet designed for 28” deep devices, such as the NetBAY42 ER, NetBAY42 SR, or NetBAY25 SR. Although the x440 system is rack optimized, it may be converted into a tower by installing it in a NetBAY11 SR Standard Rack Cabinet. The NetBAY11 rack supports shipment of fully configured xSeries 440 and other rack-optimized xSeries servers.

Installation considerations include the following:

￿The system is not designed to run vertically, and therefore must always be run in a horizontal position.

102IBM ^xSeries 440 Planning and Installation Guide