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how to increase throughput on 3com 4500 switch??
we just replaced a bad switch in our server room and we noticed that our backup is now taking 12 hours to complete when before it was taking 5 hours to complete. all our servers are plugged into this new switch which is a 3com 4500. all the ports are set to auto and they go from 10mbps-1000mbps. when we look at the backup server it is showing that the NIC is transmitting only at 100mbps. how do i increase this to get it to transmit at 1000mbps again. for example before the switch replacement the backup was doing a rate of 1700MB per minute and now after the swtich replacement it is doing a rate of 645mbps. how do i fix this??
I would suspect a negotiation issue. Although auto negotiation has come a long way there are still issues at times. These will exhibit themselves as CRC errors generally. First thing I would do is look at the interface statistics for the port the server is connected to. Use the "display interface" command.
Next would be to "nail up" the speed and duplex on the port connected to the server as well as the server itself. I would try Gig full duplex on both first. Do this with the "speed 1000" command from the correct interface. Also do the "duplex full" command.
This should fix your issue. there are other possibilities however such as faulty cabling or excessive errors. The switch actually senses line condition and can downgrade the speed if there are issues with the cabling. It could also be that 100Mb works over the typical 4 wires required for Ethernet but 1000Base will not work as it uses all 8 conductors.
Next would be to "nail up" the speed and duplex on the port connected to the server as well as the server itself. I would try Gig full duplex on both first. Do this with the "speed 1000" command from the correct interface. Also do the "duplex full" command.
This should fix your issue. there are other possibilities however such as faulty cabling or excessive errors. The switch actually senses line condition and can downgrade the speed if there are issues with the cabling. It could also be that 100Mb works over the typical 4 wires required for Ethernet but 1000Base will not work as it uses all 8 conductors.
ASKER
awesome help. now how would i do what you stated below
"Next would be to "nail up" the speed and duplex on the port connected to the server as well as the server itself. I would try Gig full duplex on both first. Do this with the "speed 1000" command from the correct interface. Also do the "duplex full" command."
how would i do this on the server and the switch?? all my servers are plugged into this switch they all have gig NIC's in them so how would i do this??
"Next would be to "nail up" the speed and duplex on the port connected to the server as well as the server itself. I would try Gig full duplex on both first. Do this with the "speed 1000" command from the correct interface. Also do the "duplex full" command."
how would i do this on the server and the switch?? all my servers are plugged into this switch they all have gig NIC's in them so how would i do this??
Well, for the switch you can either do it from the command line or console using the commands I mentioned or you can do it from the web interface under the port settings. Did you configure the switch initially?
For the server(s) it depends on the OS and/or manufacturer of the NIC card. In general you would go to the ethernet adapter properties, select configure to configure the NIC hardware and select 1000Mb/s full duplex instead of Auto.
For the server(s) it depends on the OS and/or manufacturer of the NIC card. In general you would go to the ethernet adapter properties, select configure to configure the NIC hardware and select 1000Mb/s full duplex instead of Auto.
ASKER
awesome. thank you. the servers that we have are all IBM servers and i believe they are broadcom NICs does that help??
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ASKER
awesome thank you so much. i will try this tomorrow and post back
cheers
cheers
Shouldn't be too difficult. Good luck!
ASKER
ok i tried to set the NIC to 1000Mb/s on the server and when i look at the NIC properties under advanced then speed & duplex it only has settings for 10mb and 100mb full and half duplex. the NIC cards that i have in the server are Broadcom NetXtreme Gigabit ethernet cards. why can i not set it to 1000??
Good question. I guess it could be the wrong NIC installed or a driver issue. Could also be the incorrect NIC. Most machines these days have multiple NIC cards.
ASKER
yes it does have multiple NIC cards but we are only using one of them. the NIC cards that are in the server are the ones that came with it. i am looking into the drivers now. the server is an IBM xseries 306m. do you know of any drivers that could fix this??
Here is the link for downloading drivers for the System X series of servers:
http://www-947.ibm.com/systems/support/supportsite.wss/brandmain?brandind=5000008
http://www-947.ibm.com/systems/support/supportsite.wss/brandmain?brandind=5000008
ASKER
thank you i went to the ibm site to and saw the same thing. i am going to try an update the driver and see if that produces anything. also i am going to call ibm and my switch vendor to see if they have any input. thank you very much for your help
I would also check if there is a software update for the switch.
http://www.3com.com/products/en_US/detail.jsp?tab=support&pathtype=support&sku=WEBSW4500SYS
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