Dynamic Server 9.40 introduced the following chunk features that cannot be reverted:
* Chunks greater than 2 GB in size
* Chunk offsets greater than 2 GB in size
* More than 2047 chunks
These features are enabled by default in version 10.00. The onmode -BC command has the following options that allow you to stage your migration to these features:
* onmode -BC 1
Allows chunks and offsets of greater than 2 GB to be created, but dbspaces and blobspaces that do not contain large chunks remain in the Version 9.3 format. After a chunk larger than 2 GB is added to a dbspace or blobspace, then all chunks added or altered in that dbspace or blobspace are in the new format. To revert, drop any dbspaces or blobspaces that use the new chunk features.
* onmode -BC 2
Enables the new chunk features for all dbspaces and blobspaces. Any chunk or offset added or modified has the new format. All page writes are in the new format, including those to chunks that were created prior to Version 9.40. After you issue this command, reversion to a version before 9.40 is no longer possible.
After executing either of these commands, perform a complete system level-0 backup.