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khgrant
Cisco Employee

NSO 4.1 - CDB Replication

 

Hi guys,

 

 

Could someone please advise what is the command line to check on the cdb replication settings ? for both operational data and configuration data.

 

 

Below is a snippet captured from NSO4.1 admin guide, operational data is always replicated the same way as configuration data will be replicated, and operational data is always replicated asynchronously, how would it be configured to replicate synchronously then ?

 

 

 

 

Thanks

 

Best Regards,

 

BaoYi Chai

 

5 REPLIES 5
khgrant
Cisco Employee

 

Hi Bao,

 

 

If you check “man ncs.conf”, the available to change from sync to async is:

 

 

       /ncs-config/cdb/replication (async | sync) [sync]

 

           When CDB replication is enabled (which it is when high-availability mode is

 

           enabled, see /ncs-config/ha) the CDB configuration stores can be replicated either

 

           asynchronously or synchronously. With asynchronous replication, a transaction

 

           updating the configuration is allowed to complete as soon as the updates have been

 

           sent to the connected slaves. With the default synchronous replication, the

 

           transaction is suspended until the updates have been completely propagated to the

 

           slaves, and the subscribers on the slaves (if any) have acknowledged their

 

           subscription notifications

 

 

 

However, I would use this with great care. You really need to know what you are doing.

 

 

I do not believe you can set the operational data to be sync but I think the documentation is confusing as it mentions:  /ncs-config/cdb/operational/

 

replication, which I can’t find in the man page.

 

 

I will kick an internal question and go back to you about that setting.

 

 

Roque

 

khgrant
Cisco Employee

 

Hi Roque, Thanks for the response.

 

 

i’m checking this in our setup – local HA with 1 slave node, within the ncs.conf, nothing was defined for replication settings, see below snippet of cdb section. Does this means the default replication, synchronous ? Replication verified to be working fine, service created on Master is available on Slave when NSO failover.

 

  <cdb>

    <db-dir>${NCS_RUN_DIR}/cdb</db-dir>

    <!-- Always bring in the good system defaults -->

    <init-path>

      <dir>${NCS_DIR}/var/ncs/cdb</dir>

    </init-path>

  </cdb>

 

 

Thanks for the follow up on the other query regarding operational data.

 

 

Thanks

 

Best Regards,

BaoYi Chai

 

khgrant
Cisco Employee

 

Hi Bao,

 

 

Yes, in general if there is no setting in your ncs.conf, the default value applies. The default value is shown between [] in the man page (in this case default=sync).

 

 

Regards,

Roque

 

khgrant
Cisco Employee

 

Bao,

 

 

I would like to reinforce what Roque points out. The replication will sometimes *lose transactions* if you choose async mode, unless you have other mechanisms in place to guard against this. Don't choose async unless you have thought through all scenarios in detail.

 

 

Best Regards,

 

/jan

 

khgrant
Cisco Employee

 

Hi Roque, Jan: Noted, thanks.

 

 

Thanks

 

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