Re: Why is the iSeries so slow -- MIDRANGE-L

Y'all

Here's some stuff from IBM on network setup for performance, from an article on Domino performance <http://www-919.ibm.com/servers/eserver/iseries/developer/domino/perform/perform_400.html#tune>. I went looking because the mention of MTU = 1496 triggered a memory - IBM recommends 1492 for 802.3. Anyway, here goes:

Network Tuning The main items that are of concern here are the Maximum Transmission Unit size for the line description, send and receive buffer size, port filtering, and duplex settings. For the recommendation for each of these areas read on. Maximum Transmission Unit (MTU) Size: The Maximum Transmission Unit Size (MTU) parameter affects the actual size of the line flows. By increasing the value of this parameter you can reduce the overall number of transmissions, and therefore, increase the potential capacity of the CPU and the IOP (input/output processor). Similar parameters also exist on the client. The negotiated value will be the minimum of the server and client (and perhaps any bridges/routers), so increase them all. The recommended setting varies depending on the communications protocol that is being used: · 4 MB Token Ring = 4060 · 16 MB Token Ring = 16388 · Ethernet 802.3 = 1492 · Ethernet version 2 = 1500 To change the MTU size, do the following: Type CFGTPC on any command line. You see the Configure TCP/IP display. From the Configure TCP/IP display, select option 2 (Work with TCP/IP Routes) and press Enter. You see the Work with TCP/IP Routes display. From the Work with TCP/IP Routes display, type "2" in the Opt column next to the IP address used by your Domino server. You will see the Change TCP/IP Route display. On the Change TCP/IP Route display, type in the recommendation from above in the Maximum transmission unit (MTU) parameter. TCP/IP Buffer Size: Web serving performance can be increased by tuning the buffer size that is used by TCP/IP, especially when sending large amounts of data. If your network is very reliable, try increasing the buffer size from the default (8000) to 64000. If your network experiences a significant amount of collisions or congestion, you may be able to improve performance by decreasing the TCP/IP send and receive buffers. This is because it will take less time to detect a bad packet, and less data will need to be re-transmitted. To change the buffer size, do the following: From a command line, type CFGTCP. From the Configure TCP/IP display, select option 3 (Change TCP/IP Attributes). On the Change TCP/IP Attributes display screen, locate the TCP receive buffer size (TCPRCVBUF) and type a new value. Locate the send buffer size (TCPSNDBUF) and type a new value. Press Enter.

HTH

Vern

At 12:06 PM 8/13/2003 -0400, you wrote:

Marty / Ken / Kirk,
This thread intrigues me because I have a client with a 270 and both a T/R and
100M ethernet subnets.  FTP times are fine on both subnets, though the 100M is
faster.  Even the T/R is significantly faster than it was on a CISC model 200,
going to the same local PC.
Originally they were T/R only on the 200, and have both T/R and ethernet on the 270. The T/R is used for pre-existing PCs; ethernet for any new PC's added.

They haven't had any issues with performance with both interfaces active -- until Monday (two days ago). As a point of reference, the ethernet card is not configured as *AUTO, it is set to 100M and *Half duplex with a frame size of 1496. The T/R card is set to 16M *Half, and a frame size of 16393. Forwarding it turned on to allow traffic between the two subnets.