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  • 1.  Disks for 4TB

    Posted Oct 06, 2020 12:53 PM


    We are going to mount a vsan cluster with 3 nodes and we need the total capacity of the space available for the machines to be 4 TB. Counting that we are going to mount all flash and raid 1, what total disk space do I need to buy? I know you need to keep a cache space, but I'm not sure how much you need.


  • 2.  RE: Disks for 4TB

    Posted Oct 06, 2020 03:12 PM

    Take a look to https://vsansizer.vmware.com/ or VMware® vSAN™ Design and Sizing Guide | VMware

    In a AFA configuration the "cache" disk is only for buffering the writes. So it depends on how much writes you expect.  Normal drive size would be between 400-800 GB (iirc in early vsan version the was a 800gb "limit").  The "buffer" device doesnt count into capacity calculation.  So 4TB VMs *2 (RAID1) + Witnesses + vSAN Overhead + Free space = needed space. Something like a couple of 960GB RI SATA/SAS SSD for example.

    You can lurking to the ReadyNodes configuration from HPE/DellEMC if you like.