# Filesystems

# ZFS Deduplication and Compression

Q: Is deduplication of ZFS negativly affected by putting compressed files on it?

A: Yes. Tested by putting similar files (files that well dedup) on a volume in compressed format (RAR5) and completely uncompressed the files from the archives. Maybe different on other compression algorithms?

Data:

<table border="1" id="bkmrk-compressed-raw-%28vm%29-" style="border-collapse: collapse; width: 100%; height: 296px;"><colgroup><col style="width: 50.0494%;"></col><col style="width: 50.0494%;"></col></colgroup><tbody><tr style="height: 29.6px;"><td style="height: 29.6px;">compressed</td><td style="height: 29.6px;">  
</td></tr><tr style="height: 29.6px;"><td style="height: 29.6px;">raw (vm)</td><td style="height: 29.6px;">136 GB</td></tr><tr style="height: 29.6px;"><td style="height: 29.6px;">vol (hypervisor)</td><td style="height: 29.6px;">136 GB (no compression as data already compressed)</td></tr><tr style="height: 29.6px;"><td style="height: 29.6px;">zvol (hypervisor)</td><td style="height: 29.6px;">103,4 GB (light deduplication)</td></tr><tr style="height: 29.6px;"><td style="height: 29.6px;">uncompressed</td><td style="height: 29.6px;">  
</td></tr><tr style="height: 29.6px;"><td style="height: 29.6px;">raw (vm)</td><td style="height: 29.6px;">297 GB</td></tr><tr style="height: 29.6px;"><td style="height: 29.6px;">vol (hypervisor)</td><td style="height: 29.6px;">248 GB (hv compression)</td></tr><tr style="height: 29.6px;"><td style="height: 29.6px;">zvol (hypervisor)</td><td style="height: 29.6px;">59,7 GB (massive deduplication)</td></tr></tbody></table>