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Question

DDB lookup very high percentage (98%) of backup load with 68% deduplication savings

  • December 22, 2024
  • 2 replies
  • 77 views

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 Here is a screenshot of the current status of the ddb.   Backups are running over desired time windows with 98.27% of load being ddb lookups.   We are close to capacity currently with backup storage though this will be resolved soon.   How can we resolve the high DDB lookup % issue?

DDB and job status screenshots below. 

 

 

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  • Vaulter
  • December 23, 2024

Hi ​@Paul D NZ,

Here the issue is with the Q&I value. The average Q&I time is the average time (in micro seconds) that was taken for insertion and query of signature in the deduplication database.  

 

https://documentation.commvault.com/2024e/expert/monitoring_deduplication_database_partitions.html

  • As per the screenshot, the backend size of store ID:17 is 70.52 TB
  • Also, the "Garbage collection" has been enabled.
  • I hope the respective MA is associated only with the store ID:17
  • 1 Node, 1 SSD disk per node will support up to 75 TB. This will be under "Medium" range.

https://documentation.commvault.com/v11/expert/hardware_specifications_for_deduplication_mode.html

  • For this workload we require "600 GB SSD Class Disk 1,2 2 GB Controller Cache Memory7 For Linux, the DDB volume must be configured by using the Logical Volume Management (LVM) package" disk.
  • 5K dedicated Random IOPS

https://documentation.commvault.com/2024e/expert/testing_iops_of_deduplication_database_disk_on_windows.html

  • Please let us know whether the DDB disk is hosted from a local SSD disk.
  • Is it configured from a dedicated RAID or shared with any other resource. Also, share the IOPS details.

Please refer to the below document, to run the IOmeter test to validate the IOPS.

https://documentation.commvault.com/2024e/expert/testing_iops_of_deduplication_database_disk_on_windows.html

 

Regards,

Wasim


Onno van den Berg
Commvault Certified Expert
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Paul D NZ wrote:

 Here is a screenshot of the current status of the ddb.   Backups are running over desired time windows with 98.27% of load being ddb lookups.   We are close to capacity currently with backup storage though this will be resolved soon.   How can we resolve the high DDB lookup % issue?

DDB and job status screenshots below. 

 

 

Make sure your DDB is hosted on a SSD, preferably one that is NVMe connected, and if this is already the case then you should look into the specs and health state of the drive. 


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