Intel 7xx Servers manual Further notes about IXS/IXA Disk Operations, CPW per 1k Disk Operations

CPW per 1k Disk Operations

6 00

Ops/sec

5 00

4 00

3 00

/ 1k

CPW

2 00

1 00

0

1k Write

2k Write

4k Write

8k Write

16k Write

24k Write

32k Write

64k Write

512 Read

FileServ

AppServ

512 Write

1k Read

2k Read

4k Read

8k Read

16k Read

24k Read

32k Read

64k Read

512 RW

1k RW

2k RW

4k RW

8k RW

16k RW

24k RW

32k RW

64k RW

iSCSI IXS/IXA w Caching Disabled or Shared IXS/IXA w Caching Enabled

The charts shows the relative cost when performing 5 different types of operations14.

yRandom write operations of a uniform size (512, 1k, ... 64k).

yRandom read operations of a uniform size (512, 1k, ... 64k).

yA 35% random write, 65% random read mix of operations with a uniform size (termed transaction processing type load).

yA fileserving type load - which consists of a mix of operations of various sizes similar in ratio to typical fileserving loads. This load is 80% random reads.

yAn application server - database type load. This is also a mix to simulate the character of application and database type accesses - mostly random with about 40% reads.

17.4.1 Further notes about IXS/IXA Disk Operations

yMaximum disk operation size supported by the IXS or IXA is 32k. Thus, any Windows disk operations greater than 32k will result in the Windows operating system splitting the operation into 2 or more sequential operations.

yThe IXS/IXA cost calculation is slightly greater on a POWER5® system (System i5) than on earlier 8xx systems. This includes some increased overhead costs in V5R4, and the new processor types. Use the newer rules of thumb listed above for CPW calculations.

yIt does not matter if a storage space is linked statically or dynamically, the performance characteristics are identical.

yIt does not matter if a server is an IXS or an IXA attached System x server, the disk performance is almost identical.

14Measured on a System i Model 570 - 2-way 26F2 processor (7495 capacity card), rated at 6350 CPWs, V5R4 release of i5/OS, 40 parity protected (RAID 5) 4326 disks, 3 2780 disk controllers. The IXA attached server was a x365xSeries (4way 2.5Ghz Xeon with IXA and Windows Server 2003 with SP1. The iSCSI servers were HS20 BladeCenter servers with a copper iSCSI (p/n 26K6489) daughter card. Switches were Nortel L2/3 Ethernet (p/n 26K6524) and Cisco Intelligent Gigabit Switch (p/n )

IBM i 6.1 Performance Capabilities Reference - January/April/October 2008
© Copyright IBM Corp. 2008	Chapter 17 - Integrated BladeCenter and System x Performance	287