Customer noticed that the DFWorks UDH App service had stopped running on the DFWorks server. When checking Task Scheduler the process "OraVSSW.exe" is using most of the system memory.
Volume Shadow Copy Service (VSS) is a Windows shadow copy utility used in conjunction with the Veeam Backup VSS integration. The Oracle VSS writer supports log, copy, full, differential, and incremental backups, just like RMAN.
Oracle 11g has a component named "Oracle VSS Writer" that gets installed when selecting Windows OCI Components on the Oracle 11g database install wizard of the DBCA. Veeam starts windows VSS agent and VSS starts Oracle VSS Writer, does the full consistent hot-backup of the database and then I use a script to clean archive logs and traces manually.
The web is full of reports of:
- Slow backup performance on large databases.
- VEEAM causing system-wide lock-ups.
- Memory leaks when using VSS, and many people recommending periodic bouncing of the VSS service to release memory leaks.
In a nutshell, VSS has issues and RMAN is recommended instead of VSS for performing backups on Windows systems.
However, there are known issues with VSS, most related to memory leaks and excessive memory consumption.
Cause: The problem is caused by a memory leak in the Oracle Volume Shadow Copy Service.
Solution: There is no fix for this. However, the problem can be worked around as follows:
- If not using the Windows Volume Shadow Copy Service (VSS) feature, then simply disable the ORAVSSW.EXE service (Oracle service OracleVssWriterSMARTDB).
- If VSS is being used, then simply stop and restart the ORAVSSW.EXE service after performing your disk shadow backup.
In short, RMAN is the recommended backup method for all Oracle databases on all platforms.
UPDATED: April 21, 2017