DFSR Service 100% CPU Usage

I had an enterprise DFSR customer of mine with 17 File Server nodes complaining that CPU utilisation was at 100% on numerous DFSR nodes in the cluster.

In addition to the DFSR.exe process maxing out CPU on the file server, the following error was being generated on a regular basis:

Log Name:      Application
Source:        ESENT
Date:          7/07/2016 2:33:18 PM
Event ID:      623
Task Category: Transaction Manager
Level:         Error
Keywords:      Classic
User:          N/A
Computer:      SERVER.DOMAIN.LOCAL
Description:
DFSRs (1696) \\.\E:\System Volume Information\DFSR\database_5AAC_EEEA_ACEE_C01D\dfsr.db: The version store for this instance (0) has reached its maximum size of 127Mb. It is likely that a long-running transaction is preventing cleanup of the version store and causing it to build up in size. Updates will be rejected until the long-running transaction has been completely committed or rolled back.
Possible long-running transaction:
 SessionId: 0x00000032FFE94EC0
 Session-context: 0x00000000
 Session-context ThreadId: 0x00000000000012BC
 Cleanup: 0
 Session-trace: 32997@2:32:18 PM

 

After speaking with the Directory Services team at Microsoft, this was due to a bug with KB3156418.  This was documented on the knowledge base website:

 

https://support.microsoft.com/en-us/kb/3156418

 

Symptoms
If you installed update rollup 3156418 on Windows Server 2012 R2, the DFSRS.exe process may consume a high percentage CPU processing power (up to 100 percent). This may cause the DFSR service to become unresponsive to the point at which the service cannot be stopped. You must hard-boot affected computers to restart them.

Workaround
To work around this problem, uninstall update rollup 3156418.

Status
Microsoft is aware of this problem and is working on a solution.

Make sure you do not install KB3156418 on any DFSR nodes until this issue has been fixed by Microsoft.

 

Need assistance with this issue?  Contact Avantgarde Technologies for IT Support in Perth.