This article discusses issues that may be found when using ShadowSnap's VSS backups as well as Oracle's Intellisnap backup engine.
As discussed in this article via IntelliSnap, there is a known issue with the Oracle Intellisnap backup and the Oracle VSS writer:
"There is a known issue with Oracle VSS Writer memory leak (metalink ID 1358570.1). Hence, if Oravssw.exe consumes more memory, restart the service."
We have found this issue with Oracle 11 specifically, although other versions may be affected. Our findings have shown that this memory leak can eventually make its way into the pagefile of a device and cause a server to run out of memory, hindering all server operations. Restarting the service is a good start for this. If you'd like less VSS processes to be occurring, you can switch to the STC Backup Engine in the configure agent settings page, but the issue may still persist in the Oracle VSS writer.
Should the issues persist, it is recommended to contact Oracle support for further assistance in regards to this error.