Hi Ben Thanks so much for your kindly reply. On 2019/6/12 20:07, Benjamin Coddington wrote: > Hi Jianchao, > > On 12 Jun 2019, at 3:55, Jianchao Wang wrote: > >> Hi >> >> I'm trying to setup a pNFS experiment environment. >> And this is what I have got, >> VM-0 (DS) running a iscsi target >> VM-1 (MS) initiator, mount a XFS on the device, and export it by NFS with pnfs option >> VM-2 (Client) initiator, but not mount, running a blkmapd >> mount the shared directory of VM-1 by NFS >> >> And it semes to work well as the mountstatus >> LAYOUTGET: 14 14 0 3472 2744 1 1381 1384 >> GETDEVICEINFO: 1 1 0 196 148 0 5 5 >> LAYOUTCOMMIT: 8 8 0 2352 1368 0 1256 1257 >> >> The kernel version I use is 4.18.19. >> >> And would anyone please help to clarify following questions ? >> 1. Can I involve multiple DSs here ? > > Yep, you can add a new iSCSI DS with another filesystem and keep the same > MD. The pNFS SCSI layout has support for multi-device layouts, but I don't > think anyone has put them through the paces. > > The sweet spot for pNFS SCSI is large-scale FC where the fabric allows nodes > different paths through different controllers. I expect the do-it-yourself > with iSCSI target on linux to have a bit more limited performance benefits. > >> 2. Is this stable enough to use in production ? How about earlier version, for example 4.14 ? > > Test it! It would be great to have more users. > > It would also be great to hear about your workload and if this shows any > improvements. Our workload includes large video files or massive small picture files from multiple clients I will try to setup an environment in real hardware and see what will happen then > > Last note - with SCSI layouts, there's no need to run blkmapd. The kernel > should have all the info it needs to find the correct SCSI devices. > > Ben Regards Jianchao
