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TB071 Windows-Based VDBs and Data Sources May Experience Reduced Performance




Alert Type

Functional Regression


Operations on Windows-based Virtual Databases (VDBs) and dSources may experience substantially degraded performance compared to the same operations on unaffected Delphix releases. Impacted operations include:

  • VDB database write operations, leading to overall poor VDB performance
  • Data ingestion via Full, Differential, Transaction Log or Delphix Managed Backups, leading to slow creation of dSource snapshots
  • Windows Extensible Data Source Integration (EDSI) vFiles dSource snapshot creation

Affected operations may be up to an order of magnitude slower.

Contributing Factors

The problem can only occur when running one of the following Delphix Software versions:

Major Release

All Sub Releases


Performance degradation will only occur when using iSCSI-based operations on Delphix, including:

  • MS SQL VDBs and dSources  
  • Windows-based Extensible Data Source Integrations (plugins) 
  • VDBs and dSources using vFiles on Windows

Read operations are not affected, e.g. typical VDB database read operations.

Operations on Unix and Linux dSources and VDBs are not impacted.


See Impact section above


Defer upgrades to affected Delphix releases. Upgrade to Delphix or later releases.


The pathological performance regression that is the target of this bulletin is resolved in Delphix and later releases.  Overall performance is expected to be comparable to unaffected Delphix releases, with some operations up to 10% faster or slower than in unaffected releases.

Further incremental performance optimizations are expected in a future Delphix release.


Additional Information