Motivation

IEP-43 introduces persistent caches snapshots feature. This feature highly adopted by Ignite users.

In-memory caches snapshots will simplify the following use-cases:

• In-memory cluster restarts.
• Version upgrade.
• Disaster recovery.
• DC/Hardware replacement.
• Data motion.

Description

in-memory snapshots will resuse existing snapshot code when possible. So key design decisions stay the same. It assumed that reader knows and understand IEP-43. So design description will focus on difference on persistence and in-memory snapshot.

• Persistence snapshots uses PME + Checkpoint guarantees to make sure of visibility of all dirty pages.
• Persistent pages contains CRC to make sure data integrity while storing on disk.
• StoredCacheData  save cache information on the disk for persistent caches.
• pure in-memory cluster don't store binary and marshaller metadata.

Risks and Assumptions

DataRegionConfiguration#persistenceEnabled=false  for in-memory caches by the definition.

The same value must be for DataRegionConfiguration when cache group restored from in-memory snapshot.

Discussion Links

// Links to discussions on the devlist, if applicable.

Reference Links

• IEP-43: Cluster persistent caches snapshots

Tickets