Dell Storage with Microsoft Storage Spaces Best Practices Guide

Scale-Out File Server (SOFS) shares are intended for storage of Hyper-V virtual hard disks and SQL databases. Using SOFS for information worker workloads including shares for end user file shares, containing unstructured data such as home folders, spreadsheets, or PDFs requires some additional considerations. Information worker workloads require metadata changes (file open, close, rename, delete) typically from hundreds of users at once. Scale-Out File Server shares are continuously available, which requires all nodes to synchronize metadata changes, which in the case of information worker workloads result in a potential performance overhead for these shares because of the large number of metadata changes. Based on the information worker workload, the performance impact may vary and in some cases be negligible, such as information worker workloads with newer versions of Microsoft Office. Finally, many features, which are available on a general use file shares may not work on scale-out file shares – such as DFS-R and quotas.

There are three options for providing file shares to information workers on SOFS:

Option 1: Create a SOFS on the SOFS cluster and host the information worker workload directly on the share. As long as the clients accessing the shares are using Windows 8 or later, they will receive all the benefits of using a SOFS – single namespace, load balancing, and more. Workloads on the share may experience some performance overhead because of metadata changes. Also, the scale-out file shares may not support all the features a general use file server provides like DFS-R and quotas.

Option 2: Create a new VM running Windows Server 2012 R2 and store it on a SOFS file share. Install the File Server role and configure it as a File Server for general use. Allocate the disk space (size) of the VHDX file on the basis of worker data you plan to save. Create all information worker file shares inside the VM. After the information worker workloads are run inside of a VHDX, there will be no performance overhead because of SOFS metadata changes. Also, general use file shares have the full capabilities such as DFS-R and quotas. However, because clients access general use file shares they will not receive all the benefits of accessing a SOFS. When the VM running the general-use file server is highly available on the SOFS cluster, the general use file shares running inside the VM will not be. More tasks such as clustering the guest OS may be require to provide continuously available file shares to clients.

Option 3: Create a new SMB file share on the SOFS, but modify the share after you create it by clearing the Enable continuous availability check box. By disabling the ‘continuous availability’ feature, the file share will not have performance overhead because of SOFS metadata changes. However, after the file share is not continuously available, then if access to a node in the cluster hosting the share is lost, there may be momentary loss of connectivity to the workload during the failover of the file share. In many cases, information worker workloads, such as Microsoft applications, cache data locally and a brief outage during the failover may be transparent to the user. Third-party applications may not offer the same level of data consistency, and should be evaluated on a case by case basis. Also, as long as the clients accessing the shares are using Windows 8 or later, they receive all the benefits of using a SOFS—single namespace, load balancing, and more. But, after the information worker workload is being hosted on SOFS it will not support all the features a general use file server provides such as Distributed File System Replication (DFS-R) and quotas.