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DDB Resync scheduled

  • 28 March 2022
  • 7 replies
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Userlevel 2
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Hi All,

 

maybe you have an idear. We had 2 GDSPs in the enviroment which gets the status resync scheduled. 

 

The Daily DDB Verifiy jobs running fine without any problem. 

 

The Status of the DDbs is chaning from different time. An DDb Restore was not started. 

 

 

Do you have an idear ? 

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Best answer by Orazan 27 April 2022, 13:17

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7 replies

Userlevel 2
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We had to set this key:

Name: nMaxParallelDDBResync

Category: MediaManager

Type: Integer

Value: 100 (davor war es 50 )

 

We must use 300 as value in this szenario

 

Name: nMaxDDBResyncAttempts
Category: MediaManager
Type: INTEGER
Value: 50

 

Name= nDDBResyncNWTimeoutSec
Type=MediaManager
Category=integer
value=180

Userlevel 6
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 A DDB Rsync runs in the background daily as a scheduled process.   The DDB will be online and useable, but you will see the icon until it runs.   

The Commserve and DDB are responsible for keeping track of the data being written. When a situation like a disaster recovery operation of the CommServe could potentially cause an out of sync situation especially if the CommServe Database was from an earlier point in time after new data has been written to the library. Other offline condition can lead to the tables between the CommServe and DDB to be out of sync.  In these scenarios a resynchronization of the Deduplication Database must occur.  The resynchronization process will validate and update the tables of the new archive files and pruge any archive files that are invalid such as aged data from the time of the restoration of the commserve Database.

When an inconsistency with synchronization is detected, the DDB’s are placed in maintenance mode and an automated process is run to being synchronizing.  During this time no protection operations and or pruning can occur until the resynchronization is complete.  This process uses the same logic and logging as Validation and pruning operation.  

https://documentation.commvault.com/11.24/expert/12643_deduplication_faq.html

Why do I see event messages regarding DDB engine resynchronization without running disaster recovery (DR)?
You may see event messages regarding DDB engine resynchronization even without running a disaster recovery operation because the system automatically validates the archive files in a deduplication engine and prunes the orphaned archive files. Backups are allowed to a deduplication engine during the archive file validation. This operation runs every 24 hours or 30 days depending on the number of orphaned archive files.

Userlevel 2
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Hi Again @Orazan  :)

 

so no DR, or any other situation occures. 

 

The customer is asking the following: 

 

  • Why is the resync not automaticly started when the ddb is marked as resync is scheduled
  • What does the status resync scheduled mean ? the ddb is not in maintanance right  ?
Userlevel 2
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hey @Orazan ,

 

i will ask the customer. The status of the DDb in commandcenter is Needs Resync and in the java gui resync scheduled. 

 

Looking strange. 

 

How can i find out if there is any need for an resync ? 

Userlevel 6
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There are several things that can trigger a DDB resync which is when the system checks to make sure the DDB and the CommServe database are in sync as to what records they should have.  You often see this after a DR test, A DR restore, remote DDBs losing connection to the CS periodically to name a few.

Have you done any DR testing, DR restores, or are your DDBs in remote sites?  

Userlevel 2
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Hi,

 

thanks for your quick reply. 

 

I have checked the post but cant find an solution or an awnser for my question. 

 

The DDBs in our enviroment get the Resync Scheduled status but an resync was not started. 

 

During which event or problem the DDbs get this status ? 

I checked the major events in the last 30 Days. the only event regarding the DDb was:

 

Deduplication database(s) reaching QI time threshold. on 17.03.2022 bute the DDB partitions has actually 729micro seconds ( 36% ) on both partitions. 

 

Userlevel 6
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Good morning.  Here is a link to a post that does a great job explaining the purpose of a DDB resync. 

The system also does periodic scheduled resyncs which will not put the DDB in maintenance mode..  This is a maintenance task to ensure that all is in sync.

 

Please let me know if you have any questions.