Intel 170 Servers, AS/400 RISC Server, 7xx Servers Windows CPU Cost, File Level Backup Performance

The chart above shows the CPW efficiency of operations (larger is better). Note the CPW per Mbits/sec scale on the left - as it’s different for each chart.

For an IXS or IXA, the port-based VE has the least CPW or smaller packets due to consolidation of transfers available in Licensed Internal Code. The VLAN-based transfers have the greatest cost (However the total would be split during inter-LPAR communications).

For iSCSI, the cost of using standard frames is 1.5 to 4.5 times higher than jumbo frames.

17.6.3 Windows CPU Cost

The next chart illustrates the cost of iSCSI port-based, and VLAN-based virtual ethernet operations on a windows CPU. In this case, the CPUs used are 3.2Ghz Xeon uniprocessor between HS20 BladeCenter servers. This cost is compared to operations across the external gigabit NIC connections. Again, the jumbo frames operations are less expensive than standard frames, though the external NIC is twice as efficient in General.

Streaming TCP Total Windows CPU Util

Total CPU Util per MBits/sec

1.00

0.90

0.80

0.70

0.60

0.50

0.40

0.30

0.20

0.10

0.00

External - Window s to Window s (std)

External - Window s to Window s (jumbo)

Port Based VE - Window s to Window s (std)

Port Based VE - Window s to Window s (jumbo) Vlan Based VE - Window s to Window s (std) Vlan Based VE - Window s to Window s (jumbo)

28	256	12	1024	48	4096		92	16384	8
1		5		20		1			76
						8			32

Transaction Size (bytes)

17.7 File Level Backup Performance

The Integrated Server support allows you to save integrated server data (files, directories, shares, and the Windows registry) to tape, optical or disk (*SAVF) in conjunction with your other i5/OS data. That is, this “file level backup” approach saves or restores the Windows files on an individual basis within the stream of other i5/OS data objects. It’s not recommended that this approach is used as a primary backup procedure. Rather, you should still periodically save your NWS storage spaces and the NWSD associated with your Windows server or Linux server for disaster recovery.

Saving individual files does not operate as fast as saving the individual storage spaces. The save of a storage space on a equivalent machine and tape is about 210 Gbytes per hour, compared to the approximately 70 Gbytes per hour achieved using iSCSI below.

The chart below compares some SAV and RST rates for iSCSI and an IXA attached server. These results were measured on a System i Model 570 2-way 26F2 processor (7495 capacity card). The i5/OS release was V5R4. The IXA attached comparison server was an x365 xSeries (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). The target tape drive was a model 5755-001 (Ultrium LTO 2). All tests were run with jumbo frames enabled.

IBM i 6.1 Performance Capabilities Reference - January/April/October 2008
© Copyright IBM Corp. 2008	Chapter 17 - Integrated BladeCenter and System x Performance	291