You must have an Enterprise license to use SmartIO with write-back caching for Storage Foundation or Storage Foundation High Availability.
You can set up SmartIO for write-back caching for a VxFS file system with the following configurations:
A Storage Foundation Cluster File System High Availability (SFCFSHA) cluster with exactly 2 nodes. Write-back caching is not enabled if the cluster has more than 2 nodes. If another node is added while writeback mode caching is configured, write-back caching is disabled. Caching continues in read mode.
If the cluster file system is unmounted on one of the two nodes while writeback mode caching is configured, then write-back caching is disabled. Caching continues in read mode. If the cluster file system on the second node is remounted, then write-back caching is enabled automatically.
Local mount configuration.
In the case of CFS, write-back caching uses LLT transport to mirror the write-back data. Application writes that are cached are also written to the remote cache before the write is returned.
Symantec recommends that you configure LLT over a high bandwidth network such as a 10GigE network to avoid impact to the throughput.
For information on configuring LLT, see the Symantec Storage Foundation Cluster File System High Availability Installation Guide.
The file system must have the following characteristics: