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Posted: 2016-09-13 02:00 AM . Last Modified: 2021-11-17 11:35 PM
On PME 722 and PME 8 Web Application, I have some customers which reported a very high CPU load(almost close to 100%) by w3wp.exe process.
After a lot of investigations on systems found that no any problems are reported as PME Web Application issue or other PME components but some Real time trends or Dashboard are not refresh on time or are not refresh at all.
Further investigations with some help reports of it engineers, we found that these PME servers faced with web scarping issue.
I asked customers to implement something on IT environment to prevent web scraping.
Additional I asked all to completely disable the Visitor login on PME Web and to change password for supervisor, guest and other PME application Engineering Clients and Web clients.
Fore some which do not have secure IT network asked to create insolated LAN for PME system and Clients.
Does any one faced with such issue?
Does any one have some specific ideas to prevent this issue for PME web?
At Continuous Engineering level, do we have a web scraping defending policy?
Thank you for any contribution.
Posted: 2016-09-13 07:28 AM
I haven't experienced this problem, but there's a couple things you can try to resolve this:
1). Install the latest Windows service pack and Windows security updates on the server and reboot the server.
2). Limit the amount of data that can be queued by w3wp.exe file by making this registry entry.
a). Click Start, click Run, type regedit, and then click OK.
b). Locate and then click the following registry key:
c). On the Edit menu, point to New, and then click DWORD Value.
d). Type VectorSendThrottleLimit, and then press ENTER.
e). In the right pane, right-click VectorSendThrottleLimit, and then click Modify.
f). In the Value data box, type the value that you want, and then click OK.
*** make a backup of the Windows registry before making any changes to the registry.
Posted: 2016-09-13 08:13 AM
I do remember a situation on a customer's system where the CPU and RAM was heavily utilized and the w3wp.exe process was using a lot of resources. The customer's server team added two additional quad- core processors to the server (which is a virtual machine) and this resolved the problem. This gave the server a total of 4 quad-code processors. The server has over 36,000 source/measurement pairs.
Posted: 2016-09-23 06:27 AM
Thank you Barry.
Sounds a good idea to limit the queue.
Any way, scraping can still work may be.
As i learned a few it is very difficult to prevent this issue to manifest if PME system is not part of corporate entity with a professional IT secure environment.
The better an simple i found is only LAN with high restriction or forbidden Internet access.
Posted: 2016-09-27 10:33 AM
Thanks for the thorough recommendation. I looked online and there is a range of recommendations. I also found that the wrong throttle limit could cause IIS to hang. Do you have a recommendation for the VectorSendThrottleLimit value?
Also, I noticed that this issue primarily showed up in Server 2003 and IIS6. The customer has Server 2012 with IIS 8 (image shows version below). Do you still see this working for the newer versions of Windows and IIS?
Thanks for the support!
Posted: 2016-09-27 01:53 PM
I understand Microsoft implemented multicore scaling in IIS 8.0. You may want to read how-to configure the worker process in application pools.
IIS 8.0 Multicore Scaling on NUMA Hardware : The Official Microsoft IIS Site