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 How to ensure data consistency between PVOL and SVOL prior pairsplit?

Saxena, Abhishek Saxena's profile image
Saxena, Abhishek Saxena posted 02-10-2023 15:00

I might be missing something minute, but here is my query.

Supposedly during a DR test, I would want my S-VOLs to be r/w.

On a high-level, I would follow the below steps:

  1. Bring the P-VOLs offline on the primary host.
  2. Split the pairs and make the S-VOLs r/w.
  3. Post DR test, resync the pairs overwriting the S-VOLs.

The question is, prior splitting the Pairs, how do I ensure that there is no pending data to be sent to S-VOL?

The CCI documentation reads, "Paired volumes are split as soon as the pairsplit command is issued. If you want to synchronize the volumes, the pairsplit command must be issued after write I/Os to the paired volume have completed." 

I am not sure how to ensure I/Os to secondary vols have been completed, because the pairs anyway would be in PAIR state.

I did see an option in the split mirrors window to "Flush" the data. Is that what I am supposed to be doing? If yes, how I achieve the same using CCI?

Kirsten Sven's profile image
Kirsten Sven

Hi Abhishek, 

when you want to have r/w on S-Vol after a DR-Test, means you want to simulate Powering-Off the P-Vol site ? 

See : https://knowledge.hitachivantara.com/Documents/Management_Software/SVOS/9.8.5/Global-Active_Device/11_Planned_outage_of_global-active_device_storage_systems

Section : Planned power off/on: primary storage system

Means, all the server I/O goes to the secondary storage system. 
When you direct the server I/O only to the secondary site and split/suspend the GAD pairs (pairsplit -RS) then the S-Vol has the lastet data. 
No extra flush step needed.