Dell Unity file systems allow for enhanced scalability in several different areas, including maximum file system size. Dell Unity file systems can accommodate more data, directories, and files than previous file system architectures, making Dell Unity ideal for traditional and transactional NAS use cases. The table below covers several of the scalability attributes of file systems in Dell Unity.

Table 1.      File system scalability

As of OE version 4.2, the maximum file system size is increased from 64 TB to 256 TB for all file systems, including existing file systems created on earlier code. File system sizes can range from 3 GB to 256 TB. Any attempts to create a file system with a size outside of this range results in an error. Administrators can also shrink and extend file systems to any size within the supported limits. Clients can fill up the file system with up to 256 TB of data. It is important to note that larger file system sizes result in longer backup times.

All thin file systems, regardless of size, have 1.5 GB reserved for metadata upon creation. For example, after creating a 100 GB thin file system, Unisphere immediately shows 1.5 GB used. When the file system is mounted to a host, it shows 98.5 GB of usable capacity. This is because the metadata space is reserved from the usable file system capacity. This avoids situations where creating a 100 GB file system consumes 101.5 GB of capacity out of the storage pool.