VCB snapshots causes virtual machines to lose network connectivity temporarily

[MohdAlim]

Hi,

I have the following infra in my environments:

2 x vSphere ESX 4.0 hosts (updated with latest patch)

1 x Netbackup Master 6.5.6 installed with latest VCB framework

During the VCB snapshots, 2 of my virtual machines (SQL servers) will encounter network connectivity lost. Continous ping to these servers will result in a time out. The network connectivity will resume once the VCB snapshots have been completed. I have tried to disable the quiesce file options during the backup but am still getting the network loss.

Has anyone encountered this issue before? Kindly advise.

Thanks.

[AndreTheGiant]

Which transport mode are you using?

SAN or network?

Are you trying also to do a ping from the service console of the hosts?

Andre

[MohdAlim]

I am using SAN for the VCB backup.

During the VCB snapshot process, I will perform a continuos ping from the backup server to the virtual machines, the 2 x SQL servers, during which I will get a request time out. Once the snapshot process is completed, the network is automatically restored, & backup will eventually completes successfully.

[AndreTheGiant]

Have you tried to remove and reinstall again the VMware Tools?

Andre

[MohdAlim]

Yes, did try to remove and re-install the tools but not much help though. Another thing which I realized, its only affecting if the virtual machines are residing on one of the ESX hosts. If I were to vmotion the virtual machines to the other hosts, it seems alright.

[AndreTheGiant]

The configuration of vSwitches is the same?

Same number of NICs?

Andre

[MohdAlim]

Yes, the same.

[f10]

What is the CPU usage of the VM when the snapshot is created, because in a VM all traffic is processed by the CPU. Check the performance charts or run esxtop in the esx server console where the VM is provisioned and also check the %RDY% time.

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f10

VCP3,VCP4,HP UX CSA

http://kb.vmware.com/

[MohdAlim]

The usage is actually very low. We only have 5 virtual machines for now residing on ESX1. VCB is ok when the VMs are on ESX1. But when we move some to ESX2, VCB will encounter the network connectivity loss. Both ESX1 & ESX2 have the same patch level.

[petedr]

When you get the network timeout are the snapshots large or is it happening all the time. I have seen this more with very large snapshots. If the snapshots are very large are you running any maintenance jobs inside the VM during your backup time which maybe causing larger snapshots.

www.phdvirtual.com, makers of PHD Virtual Backup for Vmware and Xen Server, formally esXpress

[MohdAlim]

It's happening all the time. But if I move it to another ESX hosts, it works fine. Still looking for the root cause.

[petedr]

Thats interesting which leads that something unique is occuring with the one host. Is maybe a resource issue ( memory or CPU ).

www.phdvirtual.com, makers of PHD Virtual Backup for Vmware and Xen Server, formally esXpress