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Additional settings and uses , can they be common for all media agents

  • 16 November 2021
  • 6 replies
  • 924 views

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Hello All, 

 

We have couple of challenges to be fixed in the environment, 

 

Aux copies:

  1. Aux copies are running sometime slow and fast and we are never able to achieve the replication completion as primary copies
  2. To reduce the data we chose to change from synchronous copies to selective copies of all full backups
  3. But still we have fallen behind copies

Environment:

5 GBPS express route from dc to azure - which is a optimal bandwidth

All backups are routed to azure blob storage through the media agents in the dc

 

Question:

These below additional setting , can be applied in common for all media agents ? All these additional settings look like they are useful in achieving the benefits expected but looking for some thoughts before apply or is good to apply them on all media agents?

DataMoverLookAheadLinkReaderSlots 

SILookAheadSimulatedAsyncIOThreadCount 

SILookAheadAsyncIOBlockSizeKB 

DataMoverUseLookAheadLinkReader

MaxCacheDBSizeMB

UseAuxcopyReadlessPlus

 

 

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Best answer by Matt Medvedeff 15 March 2022, 15:34

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6 replies

Userlevel 6
Badge +12

Before applying keys can you provide some details about the data, how much needs to get pushed daily and what speeds you are currently achieving?  

Userlevel 7
Badge +19

Mmm strange way of communicating @Commvualt Team ABB . Drop a question and never come back to it…. People take time to respond to your question so I find it a bit insulting to remain quiet,,,,,

PS: You spelled Commvault incorrectly ;-s

Userlevel 7
Badge +23

@Commvualt Team ABB are you still having this issue?  Before changing any of those settings, a full understanding of your issue and environment is needed.

Many of them are very specific in their needs.

Userlevel 4
Badge +10

Hello Team,

 

As mentioned previously, please let us know if this issue is still occurring and provide the previously requested background information.

 

There are several separate factors that cause slow performing Aux copies. The Additional Settings you are inquiring about focus mainly on Deduplication performance, so without additional info about your environment it’s hard to say whether these will help or possibly hurt the performance. Utilizing these will put additional load on the DDB Disk and Media Agent.

A quick rundown of the function of these settings:

DataMoverLookAheadLinkReaderSlots  Modifies the amount of DDB lookups when querying the Destination DDB. This can help reduce the number of small reads from the storage.
SILookAheadSimulatedAsyncIOThreadCount  Modifies the number of threads used by the above LookAhead reader.
SILookAheadAsyncIOBlockSizeKB  Tweaks the block size read by the Data Reader during any read operations on the Library.
DataMoverUseLookAheadLinkReader Toggle switch for the DataMoverLookAheadLinkReaderSlots setting. Not recommended to set to 0, on by default without the presence of this setting.
MaxCacheDBSizeMB

Defines the size of the Source-side Dedup cache, if enabled. This can help when performing DDB signature comparison on a high latency network. Can also be configured per Secondary Copy properties under the Deduplication → Advanced tab. See more here:

https://documentation.commvault.com/11.24/expert/93891_online_help.html

UseAuxcopyReadlessPlus Toggle switch to enable or disable the Source Side Dedup cache on the Media Agent. Can also be enabled in the properties of the Secondary copy at the same location as mentioned above.

 

A full explanation can be found by searching the Additional Settings documentation page - https://documentation.commvault.com/additionalsetting/?q=*

 

 

 

 

 

 

Userlevel 7
Badge +23

Hi @Commvualt Team ABB , were you able to collect the context around @MFasulo ‘s questions?

I checked your case history and don’t see an incident relating to this question.

Userlevel 7
Badge +23

@Commvualt Team ABB , following up on this one.  Is this issue still affecting you?

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