SmartIO supports the use of Solid-State Drives (SSD) exported by FSS to provide caching services for applications running on Veritas Volume Manager (VxVM) and Veritas File System (VxFS). In this scenario, Flexible Storage Sharing (FSS) exports SSDs from nodes that have a local SSD. FSS then creates a pool of the exported SSDs in the cluster. From this shared pool, a cache area is created for any or all nodes in the cluster. Each cache area is accessible only to that particular node for which it is created. The cache area can be a VxVM cache area or a VxFS cache area.

SmartIO supports write-back caching for local mounts on remote SSD devices exported by FSS. However, write-back caching is not supported on remote SSD devices for CFS environments.

If you plan to use only a portion of an exported SSD device for caching purposes, ensure that the volume used for caching is created on a disk group with disk group version 200 or later.

The volume layout of the cache area on remote SSDs follows the simple stripe layout, not the default FSS allocation policy of mirroring across hosts. If the cache area on a remote SSD needs to be resized to meet growing needs, ensure that you specify an exported device only. The operation fails if a non-exported device is specified. The cache areas can be enabled to support warm or persistent caching across reboots.

Figure: SmartIO caching with FSS-exported SSDs illustrates the caching configuration.