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VSAN Memory Minimums for Home Lab April 19, 2014

Posted by wholmes in VSAN.
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Recently there has been discussion on twitter around memory utilization of Virtual SAN for home labs scenarios. While VSAN was not designed to target home labs (Virtual SAN was designed for the enterprise) , it can be a very useful platform in enabling high performance home labs without requiring external storage. Recently Jason Nash published a blog post around his findings around memory utilization in his home lab, and his findings sparked some discussion around how VSAN memory utilization is allocated.

VSAN does have a minimum amount of memory required per host, based on the number of disk groups, and disks within each disk group. The larger the number of disk groups, and HDDs per disk group, the higher the memory utilization, up to a 10%. VSAN is designed to use no more than 10% of memory per host, even with the maximum amount of disk groups and disks. Once you have at least 32GB of memory in a host, you can support the configurable maximum, but with less memory per host, there is a sliding scale of the number of disks and disks groups that can be supported.

Below is a table detailing the minimum memory configuration based on number of disk groups and disk per disk group. This may be particularly relevant for those trying to use VSAN in a home lab.

Number of Disks

Number of Disk Groups Number of Disks per Disk Groups Minimum Memory per host
2 HDD 2 Disk Groups 2 HDD Per Disk Group 6 GB
5 HDD 5 Disk Groups 5 HDD Per Disk Group 8 GB
10 HDD 5 Disk Groups 7 HDD Per Disk Group 12 GB
15 HDD 5 Disk Groups 7 HDD Per Disk Group 16 GB
20 HDD 5 Disk Groups 7 HDD Per Disk Group 20 GB
25 HDD 5 Disk Groups 7 HDD Per Disk Group 24 GB
30 HDD 5 Disk Groups 7 HDD Per Disk Group 28 GB
35 HDD 5 Disk Groups 7 HDD Per Disk Group 32 GB