Handling of problematic disks in vSAN 6.1 – HomeLab warning

Just a quick note of caution for any other home lab users who are considering using vSAN 6.1. As part of the prep work for building the environment, it is important that if using consumer grade disks and/or bypassing some of the other HCL requirements, if there are sustained periods of high latency (which can be expected depending on how hard you push your kit), you should disable the device monitoring and unmounting process which could otherwise take your disk group offline. Whilst initially I thought this was the silver bullet to the problems I’ve been experiencing, in my scenario, it’s only been the Consumer grade SSD that disappears, not the entire Disk Group containing both the Samsung (consumer) and Intel (Enterprise) SSD.

I’ve copied the key commands below directly from Cormacs blog but I have applied *BOTH* settings in my environment.

  • Disable VSAN Device Monitoring (and subsequent unmounting of diskgroup):
    # esxcli system settings advanced set -o /LSOM/VSANDeviceMonitoring -i 0    <— default is “1″
  • Disable VSAN Slow Device Unmounting (continues monitoring):
    # esxcli system settings advanced set -o /LSOM/lsomSlowDeviceUnmount -i 0   <— default is “1″

The official VMware article on this can be found here KB2132079

Cormac Hogans blog article can be found here

One thought on “Handling of problematic disks in vSAN 6.1 – HomeLab warning

  1. Hello, glad I stumbled upon your excellent blog about consumer SSD drives and VSAN! I’m interested in purchasing 3 Supermicro servers for home use for my lab…I say lab but I’ll be treating it like a production environment. Would you mind if I asked you some questions on what flash drives to use in the setup (all flash VSAN)? The storage is the one area I am really battling with and I would like it to perform well which means the storage is key here!

    Anyway great blog, keep up the good work! Hope to hear from you!

    PS: I discovered your website from one of your posts on on the vmware forum!

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