Re: Can the PNFS blocklayout of the Linux nfsd server be used in a production environment?

["Chuck Lever" <cel@kernel.org>]

On Wed, Nov 26, 2025, at 9:14 PM, Zhou Jifeng wrote:
> Hello everyone, I learned through ChatGPT that the PNFS blocklayout of Linux 
> nfsd cannot be used for production environment deployment. However, I saw 
> a technical sharing conference video on YouTube titled "SNIA SDC 2024 - The 
> Linux NFS Server in 2024" where it was mentioned that the PNFS blocklayout 
> of nfsd has been fully maintained, which is contrary to the result given by 
> ChatGPT.
> 
> My question is: Can the PNFS blocklayout of nfsd be used for 
> production environment deployment? If yes, from which kernel version can it 
> be used in the production environment? 

Responding as the presenter of the SNIA SDC talk:

There's a difference between "maintained" and "can be deployed in a
production environment". "Maintained" means there are developers
who are active and can help with bugs and new features. "Production
ready" means you can trust it with significant workloads.

The pNFS block layout type has several subtypes. Pure block, iSCSI,
SCSI, and NVMe.

Pure block has some protocol deficiencies that prevent the ability
of the MDS to fence pNFS clients, so it might never be production
ready.

NFSD's pNFS block layout with iSCSI or SCSI works well in recent
kernels, but has some quirks that still need to be addressed. You
will have to test it with your favorite workloads to see whether
it will work for you.

NFSD's pNFS block layout with NVMe implementation is fresh from the
factory (I think the implementation went into v6.12?). As with
iSCSI/SCSI, try it and see if it works well enough for you.


-- 
Chuck Lever