Hello Stuart,Do you have access to the switch that has the connection between the VMWare server and the rest of the network?
If it's a cisco, check the command
show interfaces <interface> counters allIt will show you if the problem is in the netwerk (from that switch to the client PC) or in the vmware environment by looking at the jumbo frames counters.
Check out this document: http://www.cisco.com/en/US/products/hw/switches/ps663/products_tech_note09186a00801350c8.shtmlYou could do this step-by-step on the LAN infrastructure, and then check on the firewall / router if the jumbo frames are dropped.
There should be a way to determine (I think with SNMP) to see what packets are dropped. I would go from the switch connecting to the vmware server up the path to the client PC..
Pieter-Jan On 15 mei 2009, at 14:46, Stuart Hare wrote:
Guys I have a VMware virtaul server that is using enhanced NIC so has jumbo frames and tcp offloading enabled. And we are seeing performance issues to the app on this server. When we capture the traffic with wireshark on the server we see a hugeamount jumbo frames/packets (anywhere from 2500 to 32000 bytes), that we are not seeing on the network or end client, as well as of a lot tcp errors, in terms of bad checksums and retransmissions. On top of this each of the jumbo frames/packets have the DF bit set, which immediately tells me that these packets will be dropped by the lower default MTU on the network devices, dueto no fragmentatoin occurring.My problem is Im struggling to pinpoint this and find where these packetsare being dropped if at all.I was hoping to see this maybe from the interfaces counters on the switchesbut I see nothing. Or maybe this is happening at the physically interface of the VM host server? Is my logic around this correct or am i missing something? Cheers Stu -- Stuart Hare [email protected]
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