WinCC: "System blockage detected. Switch to Fault status."

I have the same problem with WinCC 7.5 SP1 Update 5. The configuration is Multi-User, WinCC Server, on VM on ESXi server, and two clients without project on two physical machines. We assinged enough resources to WinCC Server VM, 4GHz (min 2GHz) and 16 Gb RAM (min 8Gb), and windows is windows professional 64 bit (up to 3 clients it is allowed not to use Windows Server).

Every 2-3 weeks, sometimes 2-3 days, allways arround 6:13 PM, WinCC displays:

System blockage detected. Switch to Fault status.

And clients disconnect, there is a red arrow in WinCC icon in tray. There are few other messages after this, see attached.

We examined Windows logs, we noticed a vmware tools program sync time at this moment 6:13PM every day, but WinCC switch to faults status not every day, but turned off this vmware service just in case, and had 3 week of peace when switching to fault status happens again.

Now, in diagnose files I cannot see anything useful, and, to put simply, I am desperate.

Is there a solution of this issue?

Thank you very much

Best regards

Zoran

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Split from WinCC Clients disconnects from Server.

it's been two weeks now without failure, but I am not relaxed. Checking every day. Is there a solution maybe?

thanx

Zoran

Hi

Have you installed VMware tools on the server?

Then check if it set up to synchronize the Windows time in case you also have set up Windows to synchronize time from ntp or domain, etc.

This could cause problems.

Also make surw IT does not male backup of the running VMware server.

The problem is still not solved, in fact since I have disabled some task scheduler tasks this occurs every or every two days, always at arround 1803 hours.

I have asked IT to disable time sync from vmware tools, since I had this entry about sync time before going to fault status. I had some two months over the august and september without failure, I thought I won!, but now it is happening very often.

this is not bad idea to check whether IT guys do backup vm, will ask them,

will let you know the results,

regards

Zoran

This is the first project where I don't have access to virtual machine administration, all is done by the IT, and they do not know Siemens (even when they do, they actually don't).

This is what I did, as advised here: In the vSphere log there are entries of making snapshot of VM exactly at a time WinCC goes into fault state. By the way, if WinCC do not go into fault state, then there is loss of connection to the PLC, which is immediately recovered, all that is shown in WinCC' s process alarms. IT dept. told me that they are doing backup of VM with Veeam, which does make a snapshot as a built in feature of their backup process.

I've presented the IT dept. with Siemens 49368181_WinCC_virtualization_v2_en.pdf manual, specifically with the chapter 7.3 General recommendations, which says, among other things: 

They turned off backup for our VM, and since then, there are no going to fault nor losing connection to PLC. Process alarms list is clean.

Now, I will be monitoring this, and will get back to you to confirm that this solved the problem, or not, but I think this is it.

Btw, when I make a vSphere VM, I do follow all Siemens recommendations. Here, one more recommendation is not fulfilled, and that is Hard drive in Thick provisioned format, it is thin, hope that will not be a problem.

Many thanx to all,

Best regards

Zoran 

I have made a little compilation of backup times and WinCC going to fault, so if anyone is interested check it out. I deduce from this table that backup process, which makes snapshot of VM (as IT expert told me) is the cause of WinCC going to fault status or PLC loosing a connection. Times from the ESXi host and WinCC VM are not synchronized since I asked earlier IT to turn it off.

Just to mention, since they turned off backup process of our WinCC VM, 10 days now, there is no WinCC going to fault nor loosing a connection to PLC.

Many thanx to all of you experts!

Regards

Zoran