On Wed, 2019-02-06 at 14:44 -0800, Dan Williams wrote: > On Wed, Feb 6, 2019 at 2:25 PM Doug Ledford wrote: > > Can someone give me a real world scenario that someone is *actually* > > asking for with this? > > I'll point to this example. At the 6:35 mark Kodi talks about the > Oracle use case for DAX + RDMA. > > https://youtu.be/ywKPPIE8JfQ?t=395 I watched this, and I see that Oracle is all sorts of excited that their storage machines can scale out, and they can access the storage and it has basically no CPU load on the storage server while performing millions of queries. What I didn't hear in there is why DAX has to be in the picture, or why Oracle couldn't do the same thing with a simple memory region exported directly to the RDMA subsystem, or why reflink or any of the other features you talk about are needed. So, while these things may legitimately be needed, this video did not tell me about how/why they are needed, just that RDMA is really, *really* cool for their use case and gets them 0% CPU utilization on their storage servers. I didn't watch the whole thing though. Do they get into that later on? Do they get to that level of technical discussion, or is this all higher level? -- Doug Ledford GPG KeyID: B826A3330E572FDD Key fingerprint = AE6B 1BDA 122B 23B4 265B 1274 B826 A333 0E57 2FDD