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Posts Tagged ‘MTU’

VMware: vMotion migration socket connected returned: Already disconnected

January 7th, 2013 1 comment

Today a customer told me that he couldn’t vMotion virtual machines between a few hosts, he received this warning message:

Migration to host <<unknown>> failed with error Already disconnected

An unknown error has occurred.

vMotion migration socket connected returned: Already disconnected

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Solution:

After some troubleshooting I’ve checked and tested:

– Same VMkernel (+ case sensitive) name;
– Same VLAN;
– Same subnet;
– Same default gateway;
– They configured unique ip-addresses;
– Host A can ping host B, vice versa;
– Ping is stable < 1 ms;
– But…

…reading KB1030267 I checked the MTU size, somebody configured the MTU size with a 9000 value at the Management / vMotion VMkernel..

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The 9000 value was configured (at the hosts with the vMotion problem) but not at the physical switches, after revert to default value (1500) I was able to vMotion again, problem solved

 

Result:

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sanderdaems

Sander Daems is founder and author of this blog and working as a Lead (Sr.) Consultant by UNICA ICT Solutions. Sander has over 15 years experience in IT, primary focus: virtualization and modern worksplace.

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VMware: Edit MTU settings by GUI in vSphere 5.0

July 14th, 2011 13 comments

I saw it’s possible since vSphere 5 to configure the MTU size via the VI Client, sometimes it would be handy to do this with a GUI. In vSphere 4 you configure this at the console (vicfg-vswitch –m 9000 vswitch0 & esxcfg-vmknic –l )

vSwitch MTU Advanced Properties:

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VMkernel MTU NIC settings:

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sanderdaems

Sander Daems is founder and author of this blog and working as a Lead (Sr.) Consultant by UNICA ICT Solutions. Sander has over 15 years experience in IT, primary focus: virtualization and modern worksplace.

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Follow Me:
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