Originally posted by: ppereira

Hi, I'd like to know what speed could we get from a virtual ethernet connection between 2 lpars.
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Originally posted by: SystemAdmin

Virtual Ethernet between LPARs on a single system operate at bus speed. The RIO-2 bus operates at 2GB/s, that's 16Gb/s, or 160*100Mbs.

Of course, you will never get that kind of performance because all of the I/O traffic shares this bus, so your performance will vary depending upon how many partitions are on your machine and how many RIO ports you are using.

Different models of the POWER5 systems offer different numbers of RIO ports which limit the number of loops that you can run. Consequently, system design is very important in achieving optimal performance.
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Originally posted by: VirtualGreg

I fail to see how RIO-2 bus speeds come into play. The RIO bus is where the pSeries box goes to PCI-X adapters to do real I/O. Here we are talking about virtual ethernet which I believe is a hypervisor managed memory to memory copy. By no means does anything happen at bus speeds.

Inter-LPAR ftp test of blocks of /dev/zero to /dev/null on the other size easily gets me 100MB/sec (bytes, not bits!) with the default 1500 MTU size. A larger MTU would make this rate go up a fair bit. After all, one could never get close to gigabit speeds without using jumbo frames (9K MTU size). My test was between two LPARs in the shared pool with an entitled capacity of 0.2 processors. Available processor resources will have some impact on transfer rates.

Hopefully other readers can post their own tests.
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Originally posted by: SystemAdmin

This is an extract of data that can be found in http://publib.boulder.ibm.com/infocenter/eserver/v1r2s/en_US/index.htm
under "shared ethernet adapter sizing considerations"

112.8 MB/sec @ 80.6% processor (MTU 1500)
117.8 MB/sec @ 37.7% processor (MTU 9000)
(1.65 GHz proc, 1500 MTU, Simplex, Threading option enabled)
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Originally posted by: grukrz1

I've run test on to lpars built of virtual network ents (built on one phisical network interface) and got speed ca. 300Mbps

1. netio 10.11.23.22

NETIO - Network Throughput Benchmark, Version 1.14
(C) 1997-2001 Kai Uwe Rommel
TCP/IP connection established.
Packet size 1 KByte: 26454 KByte/s
Packet size 2 KByte: 32734 KByte/s
Packet size 4 KByte: 36155 KByte/s
Packet size 8 KByte: 37379 KByte/s
Packet size 16 KByte: 37640 KByte/s
Packet size 32 KByte: 37761 KByte/s
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