> On 1/28/25, 1:14 AM, "Christoph Hellwig" <hch@xxxxxxxxxxxxx <mailto:hch@xxxxxxxxxxxxx>> wrote: > > On Fri, Jan 24, 2025 at 08:50:02PM +0000, Day, Timothy wrote: > > While much of that has been addressed since - the kernel is a > > moving target. Several filesystems have been merged (or removed) > > since Lustre left staging. We're aiming to avoid the mistakes of > > the past and hope to address as many concerns as possible before > > submitting for inclusion. > > That's because they have a (mor eor less normal) development model > and a stable on-disk / on-the-wire protocol. > > I think you guys needs to sort your internal mess out first. > Consolidate the half a dozend incompatible versions, make sure you > have a documented and stable on-disk version and don't require > all participants to run exactly the same version. After that just > send patches just like everyone else. The network and disk format is pretty stable at this point. All of the Lustre versions released over the past 6 years (at least) interoperate over the network just fine. I don't have personal experience with a larger version difference - but the Lustre protocol negotiation is pretty solid and I've heard of larger version gaps working fine. For the disk format, Lustre uses a minimally patched ext4 for the servers. That's well documented - although perhaps a bit odd compared to NFS or SMB. The number of patches needed for ext4 has decreased a lot over time. Convergence with regular ext4 is feasible. But that's a deeper discussion with the ext4 developers, I think. My biggest question for LSF is around development model: Our current development model is still orthogonal to what most other subsystems/drivers do. But as we evolve, how do we demonstrate that our development model is reasonable? Sending the initial patches is one thing. Convincing everyone that the model is sustainable is another. Tim Day
