A guest post by Alan NG

File Systems Extension/Shrinkage

Following on from part 1 and part 2 where we covered PowerFlex SDNAS System Features and took a deeper look (and walkthrough) of support NAS protocols.

This post will cover key PowerFlex SDNas File System features such as, File System Expansion, Quotas and Data Efficiency.

File system capacity can either become full due to increasing demand or decrease due to reduced usage. Therefore, a flexible storage system that can expand or shrink storage capacity based on demand is highly desirable. PowerFlex File is designed for this purpose, as it is scalable and flexible, allowing for both expansion and shrinkage of storage capacity as needed.

Expansion: When additional storage capacity is required, PowerFlex File can easily add new storage nodes to the existing cluster, providing additional capacity and performance without disrupting existing workloads or requiring downtime. As new nodes are added, the file system automatically rebalances data across the cluster to ensure optimal performance and utilization.

Shrinkage: PowerFlex File also supports shrinking storage capacity by removing nodes from the cluster. This can be useful when capacity requirements decrease or when upgrading hardware. PowerFlex File can migrate data from the nodes being removed to other nodes in the cluster, ensuring that data is not lost, and workloads are not disrupted.


PowerFlex File supports quota management at both the user and directory level, giving administrators granular control over storage usage in the file system.

At the user level, administrators can set quotas for individual users or groups, limiting the amount of storage space each user or group can consume. This helps ensure that users do not exceed their allocated storage space, and provides a way to manage storage costs by limiting over-provisioning. Quotas can be set in terms of absolute size, as well as a percentage of the total storage space available.

At the directory level, administrators can set quotas for specific directories or subdirectories in the file system tree structure. This allows for more fine-grained control over storage usage, enabling administrators to manage storage allocation on a per-application or per-project basis. Quotas can be set recursively, allowing administrators to apply quotas to entire sub-trees of the file system.

PowerFlex File also supports nested quotas, which enable administrators to set multiple quota limits within a single directory. For example, an administrator might set a directory quota that limits the total amount of storage space that can be used in that directory, while also setting individual quotas for sub-directories within that directory. This provides greater flexibility in managing storage usage in complex directory structures.

Data Efficiency

PowerFlex File achieves data efficiency through compression, which reduces the storage space needed to store data. The solution uses a fine-granularity (FG) data pool to manage compression, giving administrators more control over the process. However, note that this increased capacity comes at the expense of performance.

PowerFlex File also supports inline compression, which means that data is compressed as it is written to disk, rather than being compressed after it has been written. This can help improve storage efficiency and reduce the overall storage footprint of the file system.

In the next post we’ll take a look at the security features available when considering PowerFlex File Services (SDNAS)

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