We have a Windows server 2012 R2 running web-based Sybase SQL & JBoss application. We have experienced very poor response time of the application. We found that the svchost.exe DHCPServer was creating many many files consuming 50-100MB/s. All files under dhcp directory consume 24GB. It seemed to max out the all available disk bandwidth causing the poor performance of the SQL query. It was none of any workstation requesting DHCP request in the LAN segment.

What is the cause? Can it be fixed? Any suggestion?

Thanks in advance, Thomason

svchost.exe(HDCPServer) High disk activity

  • There's something clearly wrong with the DHCP backup process. The server will backup the DHCP database every 60 minutes but there should not be as many backup files as is shown in your image. Stop the DHCP service, delete the backup files in the backup directory, and restart the DHCP server to see if that resolves the problem. – joeqwerty Feb 26 '19 at 14:00
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    Why are you running dhcp on an application server? – John Keates Feb 26 '19 at 17:16
  • I am a new staff. That was installed long time ago by external vendor. That network segment has only 4 inactive workstations. I would stop the dhcp server for comparison. Thanks. – Thomason FAN Feb 27 '19 at 14:43

This is not the "default" behaviour of the dhcp service. Stop the service, delete those backup files (there shouldn't be that many!) and check the eventlogs messages regarding the source DHCP.

It's hard to say what causes this, but it's definately not right. DHCP makes a backup of his JET db every 60 minutes, which usually takes no time.

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I would run a small wireshark, as I suspect a faulty device that make your DHCP server work a lot, maybe the device just request IP without accepting it in example, but we will not know until a wireshark is done.

As the device would be without IP, from the wireshark you could find the MAC, and from the switch know where it's, and maybe just block it with the MAC.

Another common cause is a faulty dhcp database, thus you could stop the service, delete/move all the log, restart the service and do a backup, in the MMC right click the server and select to make a backup, as seen in the image;

enter image description here

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