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Can we change from RF3 to RF2?

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Outrider

Can we change from RF3 to RF2?

I think it is hard to make it back to the original one but basically I have completed my test on RF3 and want to change the Redundancy factor from 3 to 2 in my cluster without reinstalling my cluster 

Really need some advice and ideas on this

 

Regards,

1 ACCEPTED SOLUTION

Accepted Solutions
Nutanix Employee

Re: Can we change from RF3 to RF2?

Hello,

 

Once a cluster is configured for RF3 it cannot be fully converted back to RF2.  You can create RF2 containers on a RF3 cluster.  However, there is not a process for scaling back the other processes involved in maintaining fault tolerance.

 

Hope this helps.

9 REPLIES
Vanguard

Re: Can we change from RF3 to RF2?

Hi,

Basically, RF (Replication Factor) had two areas, one for metadata and one for the containers. see if you can change the RF3 to RF2 on the container or simply create a new container with RF2 and migrate UVMs. For metadata try to change the RF3 to RF2 from Settings.

Let us know if it works.

 

F.P

Nutanix Employee

Re: Can we change from RF3 to RF2?

Hello,

 

Once a cluster is configured for RF3 it cannot be fully converted back to RF2.  You can create RF2 containers on a RF3 cluster.  However, there is not a process for scaling back the other processes involved in maintaining fault tolerance.

 

Hope this helps.

Outrider

Re: Can we change from RF3 to RF2?

@john_burton I got it,

 

Seems like there is no way except for recreating the cluster to get the Redundancy Factor RF2 back online. 

Thanks a lot for your information

Pathfinder

Re: Can we change from RF3 to RF2?

Hi John,   

 

Can you clarify RF3 situation.    We have a single storgage pool with one Storage Container currently using RF3,  as we can't scale that back to RF2 that's fine for now.   When creating a second storage container using RF2 this will only have 2 data/metadata copies or is there some other overhead associated with the main contanier/pool being created with RF3.  We have 2 Nutanix clusters about ot go live and this will be more effictive use of capacity for some systems such as SQL AO - 4 effictive copies on Storage Containers with RF2 instead of 6 in RF3.

 

Thanks in Advance,

Ray.

Pathfinder

Re: Can we change from RF3 to RF2?

Hi John,   

 

Can you clarify RF3 situation.    We have a single storgage pool with one Storage Container currently using RF3,  as we can't scale that back to RF2 that's fine for now.   When creating a second storage container using RF2 this will only have 2 data/metadata copies or is there some other overhead associated with the main contanier/pool being created with RF3.  We have 2 Nutanix clusters about ot go live and this will be more effictive use of capacity for some systems such as SQL AO - 4 effictive copies on Storage Containers with RF2 instead of 6 in RF3.

 

Thanks in Advance,

Ray.

Outrider

Re: Can we change from RF3 to RF2?

@Ray_McBride

 

Based on my understanding about the RF, basically RF is the act of replication and/or redundancy of VM, VG data existing in the associated container.

It means that, if a VM runs in a RF2 container, it will have 2 copies of data 

and 

if a VM runs in a RF3 container, it will have 3 copies of data across the storage pool/cluster.

 

 

Pathfinder

Re: Can we change from RF3 to RF2?

Hi Hienle - that's my understanding also... just want to be sure.  If multiple SC's can run in parallel with different RF it would negate having to rebuild the cluster to go from RF3 to RF2 - it would 'simply' be a VM move operation between the two SC's.  Although i believe multiple SC's are not recommended for performance reasons.

 

Thanks,

Ray.

Highlighted
Nutanix Employee

Re: Can we change from RF3 to RF2?

Hi Ray,

 

There are 3 primary components that define a cluster's resiliency factor:

 

  • Number of zookeeper nodes (3 for RF2, 5 for RF3)
  • Number of copies of metadata (3 for RF2, 5 for RF3)
  • Numer of copies of egroup data (2 for RF2, 3 for RF3)

 

There's no issue with using more than one storage container (SC) with different RFs configured.  Also, in current AOS versions you can change the container RF from 3 to 2 using the command:

 

  • ncli ctr edit id=<ctr_id> rf=2

 

Note that this will only affect the 3rd item - the extra egroup copies in that container will be deleted.

 

Hope this helps.

Pathfinder

Re: Can we change from RF3 to RF2?

Excellent - 

 

Having the ability to change RF in current code levels is a great feature to have.

 

Many Thanks John!