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VCS MirrorView Agent - can't use Consistency Groups in Synchronous mode?

fmthard
Level 3

Can somebody from SYMC tell us why this isn't supported (is it a MirrorView limitation?), and possibly give a timeframe when it will be?

IHAC that is constantly adding/changing LUNs in their replication schema, and this requires us to go in and change the MirrorView resource(s) associated with these changes.

This question has been asked before (https://www-secure.symantec.com/connect/forums/veritas-cluster-server-agent-emc-mirrorview) and closed, but without any solution other than "maybe you should run in async mode".

Thanks

1 ACCEPTED SOLUTION

Accepted Solutions

Wally_Heim
Level 6
Employee

Hi fmthard,

Several of the hardware replication agents only perform replication group discovery one during the start up of the cluster and cache that information in the running configuration of the cluster.  The cluster assumes that the replication configuration is not changing on a regular bases so its caching of this information is not a problem for most customers.  This caching prevents other nodes from having to discover the disks/luns used for replication and reduces the overall load on the array from VCS discovering the replication group/configuration infromation. 

Because of this caching, whenever changes are made to the replication groups/configuration the cluster needs to be made aware of it to perform the discovery process again.

I hope this helps answer your question regarding the MirrorView hardware replication agent.

Thanks,

Wally

View solution in original post

3 REPLIES 3

Wally_Heim
Level 6
Employee

Hi fmthard,

Several of the hardware replication agents only perform replication group discovery one during the start up of the cluster and cache that information in the running configuration of the cluster.  The cluster assumes that the replication configuration is not changing on a regular bases so its caching of this information is not a problem for most customers.  This caching prevents other nodes from having to discover the disks/luns used for replication and reduces the overall load on the array from VCS discovering the replication group/configuration infromation. 

Because of this caching, whenever changes are made to the replication groups/configuration the cluster needs to be made aware of it to perform the discovery process again.

I hope this helps answer your question regarding the MirrorView hardware replication agent.

Thanks,

Wally

mikebounds
Level 6
Partner Accredited

Wally, are you saying you cannot use consistency groups because the open entry point caches the contents of the consistency group and therefore if the contents of the consistency group changed then the online of a MirrorView resource would be work on the "old"  consistency group contents.

This being the case then post "https://www-secure.symantec.com/connect/forums/veritas-cluster-server-agent-emc-mirrorview" says consistency groups ARE support in async mode, so how does this work in Async mode if the open routine caches the consistency groups contents?

Mike

Wally_Heim
Level 6
Employee

Hi Mike,

 

Consistency groups are supported.  However, when you make configuration changes to the Consistency group you will need to do some manual processes to let the agent know that it needs to rediscover the new configuration details of the Consistency group.

 

Thanks,

Wally