On Tue, 4 Jun 2024 10:19:59 -0600 Logan Gunthorpe <logang@xxxxxxxxxxxx> wrote: > On 2024-06-04 06:46, Xiao Ni wrote: > > Hi Mariusz > > > > The discard can't promise to write zero to nvme disks, right? If so, > > we can't use it for resync, because it can't make sure the raid is in > > sync state. > > Yes, discard requests are a best effort and the drive is free to ignore > some or all of the request. See [1] for more information from Martin > Peterson. > > I think if we have a device that has a fast zero operation that we know > guarantees zeroing then the kernel's write-zeros operation should be > changed to use it. We shouldn't make fast-but-dangerous options in mdadm. > > Thanks, > > Logan > > > [1] https://lore.kernel.org/all/yq1fsgwbijv.fsf@xxxxxxxxxxxxxxxxxxxx/T/#u Thanks for giving the valuable feedback. I'm not directly involved in technical details about this implementation and in fact I didn't read the previous discussion yet. You pointed great problem and I will make sure that it is addressed. I asked about mdadm API, it is despite the technical implementation. I would like to propose one command to integrate existing way (--write-zeroes) and potentially new way (if any other fast-initialization capability would be safe to add). Do you see it as right approach or we should keep them separately? Mariusz
