Error Message

Slow VVR replication speed.

Because VVR has to maintain the write order fidelity, the application write operations will be serialized when they are replicated to the VVR secondary data storage.   On the VVR primary, application can issue asynchronous write operations to the disk storage, so the latency of the primary disk storage is not a major issue.   On the VVR primary, as long as the disk storage can provide sufficient I/O throughput, the asynchronous I/O mechanism can fully utilize the available I/O throughput.   But on the VVR secondary, because the write order fidelity has to be maintained, asynchronous write operations are limited.   If the write latency of the disk storage (write service time) is high, the serialized write operations to the secondary data volumes may not be able to fully utilize the write operation throughput of the secondary disk storage.

It is recommended that the write latency of the VVR secondary data storage should be minimized in order to improve the replication speed.    If high-end diskarray is used for the VVR secondary data storage, the LUNs should have proper hardware layout to minimize the write latency (write service time).   If low-end physical disks are used to create the VVR secondary VxVM volumes, the VxVM volumes can be relayouted into striped volumes to improve the write latency.