2.1.4.2 Compatibility

Except for the addition of a CVM specific magic number, CVM DRL headers are the same as their SSVM counterparts.

It is possible to import a SSVM disk group (and its volumes) as a CVM shared disk group and vice versa. However, the dirty region logs of the imported disk group can be considered invalid and a full recovery can result.

If a CVM shared disk group is imported by a SSVM system, SSVM will consider the logs of the CVM volumes to be invalid and will conduct a full volume recovery. After this recovery completes, the volume manager will use the CVM Dirty Region Logging.

CVM is capable of performing a DRL recovery on a non-shared SSVM volume. However, if a SSVM volume is moved to a CVM system and imported as shared, the dirty region log will probably be too small to accommodate all the nodes in the cluster. CVM will therefore mark the log invalid and do a full recovery anyway. Similarly, moving a DRL volume from a two-node cluster to a four-node cluster will result in too small a log size, which CVM will handle with a full volume recovery. In both cases, the system administrator is responsible for allocating a new log of sufficient size.