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Question

DDB lookup

  • 8 April 2023
  • 4 replies
  • 518 views
A
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Hi 

In below screen shot why DDB lookup is very high percent, does it mean backup job with slow performace and what could be the reason that DDB lookup percentage high  

 

 

Thanks

4 replies

MichaelCapon
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Hi Aju,

 

This simply shows that 71% of the load was in Dedup signature lookup. - Without looking into the logs I wouldn’t know how long that duration was nor how many signatures were processed.

Can you confirm the current Q&I time of the Dedup Engine here? - Is it within the acceptable thresholds?

 Are you experiencing any performance issues with the Jobs?

 

Kind Regards,

Michael

A
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Hi

Here is property dedup engine, it is newly configured Hyperscale and new SP created and assinged to some of clients so these clients is first jobs on this SP. we feel that if is slow as compare to previous SP disk library which is connected to SAN storage 

 

 

Thanks

 

MichaelCapon
Rank
Userlevel 6
Badge +14

Hi Aju,

Since this is a new DDB and SP, The first Jobs will be building the baseline here. This baseline means most likely most of the dedup signatures encountered would be inserted into DDB and Data written to Disk.

The subsequent backups (especially Full/Synth) should be able to reference already stored signatures which should accelerate those backups here.

 

I would suggest to monitor the next Jobs and let us know how it goes.

On the HyperScale nodes you can check the CVPerfMgr.log (in /opt/commvault/Log_Files/) filtered for JobID, this will tell you the performance statistics of some of the Jobs reported on, Along with the Clients Agent logs. e.g. clBackup.log for WinFS, vsbkp for VirtualServer.

 

Best Regards,

Michael

S
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Hi team,

I got the same issue as Aju with one of my client computer (Linux FS) and I am trying to get the root cause of that.

2 last nights were OK but few days ago backups were slowest than usual.

Last night (average througput 2500GB/h):

(Read: 52,70%, Write: 2,93%, Network: 5,22%, DDB lookup: 39,15%)

SigQuery-Stats: [Duration - 3600] [SIDB-Lookup - 583.12] [CLDB-Query - 0.00] [CLDB-Insert - 0.00] [Signatures processed - 3802065] [Size-Application - 1217147830272 (1133.56 GB)] [Size-Compressed - 695235484854 (647.49 GB) ] [Size-Transferred - 61173353304 (56.97 GB)]

 

October 30th (900GH/h) :

(Read: 12,81%, Write: 0,72%, Network: 3,14%, DDB lookup: 83,33%)

SigQuery-Stats: [Duration - 10802] [SIDB-Lookup - 6793.42] [CLDB-Query - 0.00] [CLDB-Insert - 0.00] [Signatures processed - 4315504] [Size-Application - 1376330334208 (1281.81 GB)] [Size-Compressed - 780068299953 (726.50 GB) ] [Size-Transferred - 106293459863 (98.99 GB)]

 

 

 

Thanks for you help,

 

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