Interaction of compressed files and other features

Table: describes how compressed files interact with other Storage Foundation features.



Interaction with compressed files

Cross-Platform Data Sharing

If you convert a disk or file system from one platform that supports compression to a platform that does not support compression and the file system contains compressed files, the fscdsconv command displays a message that some files violate the CDS limits and prompts you to confirm if you want to continue the conversion. If you continue, the conversion completes successfully, but the compressed files will not be accessible on the new platform.

File Change Log

The File Change Log feature does not detect file compressions nor uncompressions.

Shared extents (FileSnap and deduplication)

Shared extents do not get compressed.

Compressed files may be shared with the vxfilesnap command, though this results in a performance impact when accessing those files.


The SmartTier feature does not support compression. A placement policy cannot move existing compressed extents. Newly-allocated compressed extents follow the existing placement policy.

Space reservation (setext -r)

When a file is compressed, any space reserved via the setext -r command beyond the end-of-file is discarded, and is not restored when the file is uncompressed. The setext -r command cannot be used to reserve space for files that are compressed.

Storage Checkpoints

If a file system contains compressed files and you create a Storage Checkpoint of that file system, you can access those files normally through the Storage Checkpoint. However, you cannot compress nor uncompress a file that is already in a mounted Storage Checkpoint.