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.
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
