11 Replies Latest reply on Jul 24, 2020 10:06 AM by firefoxchris

    Huge File System Overhead with vSAN 6.6

    cjckalb Novice

      Hi everyone,


      we're currently demoing vSAN 6.6 on an all-flash setup. After the upgrade to vSAN 6.6, we have noticed a huge increase in file system overhead.

      With dedup & compression enabled, the file system overhead is about 1.7 TB for a 16TB vSAN.Bildschirmfoto 2017-05-15 um 20.45.41.png


      With dedup & compression disabled, the file system overhead is still about 200GB:

      Bildschirmfoto 2017-05-15 um 23.03.51.png

      Please note that both of these are empty, newly created vSAN datastores containing neither VMs any other objects. In previous releases I've seen file system overhead in the range of a couple of megabytes to maybe a few gigabytes, which also matches the screenshots in the official vSAN 6.6 documentation displaying 11.34 GB file system overhead for a 15TB array.


      Is there an explanation for that strange behavior?