Showing posts from July, 2019

Remote Copy Data Patterns and Partnership Tuning

Hello friends. I know it has been a while, but I would like to now put out part 2 to the 1920 post I had put out a while back. That post was largely around tuning the partnership to protect against impacts to the master volume (or replication source). This week I would like to explain a bit about how data is replicated to help understand why 1920 events and backpressure can happen and how to hopefully avoid the situation in the first place. Types of Remote Copy Relationships in SpecV Metro Mirror (Synchronous/Synchronous) Metro Mirror is what I call a Sync/Sync replication. By this I mean that the RPO is synchronous or in layman's terms the two sides of the mirror are always identical. Additionally, the data pattern for the replication is synchronous as well meaning we forward new writes as we receive them as shown here: When the primary host sends a write to the master volume, we will forward that to the remote cluster. The remote cluster will cache the write and send an a