AppSync: Service plan fails with VSS timeout while taking a SnapVX snapshot of a large number of SQL databases

Summary: AppSync encounters multiple VSS timeouts while taking a snapshot of more than 50 databases that are subscribed to a SQL service plan, even though there is no performance issue in the SMI-S server. ...

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Symptoms



AppSync SQL service plan fails to create a SnapVX snapshot of more than 50 databases as it encounters multiple VSS timeouts even though the SMI-S job completes in a second.
 
The AppSync VSS service encountered an exception: VSS replication failed during Thaw. See the host plug-in log and application event log for details.
The AppSync VSS service encountered an exception: Failed to create a copy after 3 retries. See the host plug-in log and application event log for details.
 

Cause

AppSync performs the below tasks during the 10 second Freeze-Thaw window:
  1. Gets all the application's file system and associated RDF device entity from persistence.
  2. Checks the RDF device status for both SRDF/A and SRDF/S.
  3. Creates SnapVX snapshot in array.
In service plans with a large number of file systems/databases in a single phase pit, the tasks required can take more than 10 seconds.

The below service plan has 55 databases subscribed to it.

AppSync Server Logs:
05-31-2018 12:25:57.513 DEBUG [EJB default - 6][com.emc.archway.entitycommands.phasepit.entity.GetPhasePitCopiesCommandBean] [<AppSync Server Name>] [] fc68ba37-5fa5-4e35-8b46-39f613dfaa67->>> Found 55 graph items of type class com.emc.archway.datamodel.ArchwayApplicationCopyStatusEntity
05-31-2018 12:26:02.185 DEBUG [EJB default - 6][com.emc.archway.entitycommands.phasepit.entity.GetPhasePitCopiesCommandBean] [<AppSync Server Name>] [] fc68ba37-5fa5-4e35-8b46-39f613dfaa67->>> Timetaken to get all the copies of phasepit 7b5d1c20-a765-4e4b-9db3-6fc38191ccdb is 4750 ms
 
05-31-2018 12:26:02.216 INFO [EJB default - 6] [com.emc.archway.entitycommands.application.entity.GetApplicationFileSystemsCommandBean] [<AppSync Server Name>] [] fc68ba37-5fa5-4e35-8b46-39f613dfaa67->>> Adding copy of SQL FileSystem E:\ to the list for mounting/unmounting/restoring
.
.
05-31-2018 12:26:12.201 INFO [EJB default - 6] [com.emc.archway.entitycommands.application.entity.GetApplicationFileSystemsCommandBean] [<AppSync Server Name>] [] fc68ba37-5fa5-4e35-8b46-39f613dfaa67->>> Adding copy of SQL FileSystem L:\ to the list for mounting/unmounting/restoring
If more than 50 SQL databases are subscribed to a service plan and protected as part of a single phase pit, all of these steps together can take more than 10 seconds.
As a result, the 10 second timeout window is breached and the service plan fails.

Resolution

Upgrade to AppSync version 3.8 to obtain the fix for this issue.

The fix moves steps 1 and 2 (source device listing and check for SRDF status) outside the VSS freeze window. 

AppSync can be downloaded from the product support page below. 

https://support.emc.com/products/25364_AppSync




Article Properties
Article Number: 000167904
Article Type: Solution
Last Modified: 18 Sept 2025
Version:  3
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