Flexible Storage Sharing use cases

The following list includes several use cases for which you would want to use the FSS feature:

Use of local storage in current use cases

The FSS feature supports all current use cases of the Storage Foundation and High Availability Solutions (Storage Foundation and High Availability Solutions) stack without requiring SAN-based storage.

Off-host processing

Data Migration:

  • From shared (SAN) storage to network shared storage

  • From network shared storage to SAN storage

  • From storage connected to one node (DAS)/cluster to the storage connected to a different node (DAS)/cluster, that do not share the storage


An additional node can take a back-up by joining the cluster and reading from volumes/snapshots that are hosted on the DAS/shared storage, which is connected to one or more nodes of the cluster, but not the host taking the back-up.

DAS SSD benefits leveraged with existing Storage Foundation and High Availability Solutions features

  • Mirroring across DAS SSDs connected to individual nodes of the cluster. DAS SSDs provides better performance than SAN storage (including SSDs). FSS provides a way to share these SSDs across cluster.

  • Keeping one mirror on the SSD and another on the SAN storage provides faster read access due to the SSDs, and also provide high availability of data due to the SAN storage.

  • There are several best practices for using SSDs with Storage Foundation. All the use-cases are possible with SAN attached SSDs in clustered environment. With FSS, DAS SSDs can also be used for similar purposes.

FSS with SmartIO for file system caching

If the nodes in the cluster have internal SSDs as well as HDDs, the HDDs can be shared over the network using FSS. You can use SmartIO to set up a read/write-back cache using the SSDs. The read cache can service volumes created using the network-shared HDDs.

FSS with SmartIO for remote caching

FSS works with SmartIO to provide caching services for nodes that do not have local SSD devices.

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 each node in the cluster. Each cache area is accessible only to that particular node for which it is created. The cache area can be of type, VxVM or VxFS.

The cluster must be a CVM cluster.

The volume layout of the cache area on remote SSDs follows the simple stripe layout, not the default FSS allocation policy of mirroring across host. If the caching operation degrades performance on a particular volume, then caching is disabled for that particular volume. The volumes that are used to create cache areas must be created on disk groups with disk group version 200 or later. However, data volumes that are created on disk groups with disk group version 190 or later can access the cache area created on FSS exported devices.


CFS write-back caching is not supported for cache areas created on remote SSDs.

For more information, see the document Veritas InfoScale SmartIO for Solid State Drives Solutions Guide.

Campus cluster configuration

Campus clusters can be set up without the need for Fibre Channel (FC) SAN connectivity between sites.