Question

Running VM with ZFS on top of Nutanix Platform

  • 21 February 2020
  • 2 replies
  • 2704 views

I run a 6-node nutanix cluster, and planing to run some containers (LXC) , inside VM using ZFS pool, to leverage on easy clone, migrate, snapshot the containers mainly to transport those clones to other system (DR)

I read that ZFS need to deal directly with disks hardware to be sure about what is or what is not actually written to disks. 

Is ZFS suaitable or not, being run on top of nutanix platform, concerning the data corruption risk or losing pool, because it can’t deal directly with disk hardware?

Hardware is supermicro bundled with nutanix-enterprise.


2 replies

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hello @zain 

It sounds like you’re already aware of some reasons why ZFS may not perform as expected in a virtual disk. From reviewing the available documentation they caution against implementing on top of another filesystem with warnings of performance losses and other potential issues.

I’ll add that any disk health monitoring features included in ZFS would be nonsensical at best when applied to a VM disk on the Nutanix distributed filesystem. ZFS seems designed to make good use of (cheaper) commodity hardware and included some disk health monitoring and disk-device tweaks to do so. Any filesystem block in ZFS could be part of one or more filesystem blocks in the Nutanix Distributed FileSystem (DFS), and any of those DFS blocks would reside on two or more physical disks in the cluster and would likely migrate between the SSD and HDD tiers during the lifecycle of the data. Because of this any attempt to recognize and monitor the underlying physical device simply couldn’t rely on it being the same device from one hour to the next.

I would recommend reviewing the Docker Storage Considerations section of the Docker Containers on AHV  best practices guide, and determining whether the same reasoning and recommendations can be successfully applied to your deployment. While Docker won’t be quite the same thing as LXC, it’s the closest analog that’s been thoroughly vetted and you’ll see the authors took the time to consider ZFS among other available options before forming their recommendations.

 

dear @JeremyJ ,

 

thank you for your explanation. I already thought that is the case about ZFS on DFS,  I need to be sure.

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