[gpfsug-discuss] AFM-DR Questions

[Venkateswara R Puvvada]

Hi,

> - Any reason why we changed the Recovery point objective (RPO) snapshots 
by 15 minutes to 720 minutes in the version 5.0.0 of IBM Spectrum Scale 
AFM-DR?

AFM DR doesn't require RPO snapshots for replication, it is continuous 
replication. Unless there is a need for crash consistency snapshots 
(applications like databases need write ordering), RPO interval 15 minutes 
simply puts load on the system as they have to created and deleted for 
every 15 minutes.
 
>- Can we use additional Independent Peer-snapshots to reduce the RPO 
interval (720 minutes) of IBM Spectrum Scale AFM-DR?

Yes, command "mmpsnap --rpo" can be used to create RPO snapshots. Some 
users disable RPO on filesets and cron job is used to create RPO snapshots 
based on requirement.
 
>- In addition to the above question, can we use these snapshots to update 
the new primary site after a failover occur for the most up to date 
snapshot?

If applications can failover to live filesystem, it is not required to 
restore from the snapshot. Applications which needs crash consistency will 
restore from the latest snapshot during failover. AFM DR maintains at most 
2 RPO snapshots.

 >- According to the documentation, we are not able to replicate Dependent 
filesets, but if these dependents filesets are under an existing 
Independent fileset. Do you see any issues/concerns with this?

AFM DR doesn't support dependent filesets. Users won't be allowed to 
create them or convert to AFM DR fileset if they already exists.


~Venkat (vpuvvada at in.ibm.com)



From:   "Delmar Demarchi" <delmard at br.ibm.com>
To:     gpfsug-discuss at spectrumscale.org
Date:   03/29/2018 07:12 PM
Subject:        [gpfsug-discuss] AFM-DR Questions
Sent by:        gpfsug-discuss-bounces at spectrumscale.org



Hello experts.

We have a Scale project with AFM-DR to be implemented and after read the 
KC documentation, we have some questions about.  

- Do you know any reason why we changed the Recovery point objective (RPO) 
snapshots by 15 to 720 minutes in the version 5.0.0 of IBM Spectrum Scale 
AFM-DR?
 - Can we use additional Independent Peer-snapshots to reduce the RPO 
interval (720 minutes) of IBM Spectrum Scale AFM-DR?
 - In addition to the above question, can we use these snapshots to update 
the new primary site after a failover occur for the most up to date 
snapshot?
 - According to the documentation, we are not able to replicate Dependent 
filesets, but if these dependents filesets are part of an existing 
Independent fileset. Do you see any issues/concerns with this?

Thank you in advance.

Delmar Demarchi .'.
(delmard at br.ibm.com)_______________________________________________
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