On Wed, Jul 24, 2019 at 03:03:07PM +0800, Wei Yang wrote: > Persistent backend setup requires some knowledge about nvdimm and ndctl > tool. Some users report they may struggle to gather these knowledge and > have difficulty to setup it properly. > > Here we provide two examples for persistent backend and gives the link > to ndctl. By doing so, user could try it directly and do more > investigation on persistent backend setup with ndctl. > > Signed-off-by: Wei Yang <richardw.y...@linux.intel.com> > --- > docs/nvdimm.txt | 28 ++++++++++++++++++++++++++++ > 1 file changed, 28 insertions(+) > > diff --git a/docs/nvdimm.txt b/docs/nvdimm.txt > index b531cacd35..baba7a940d 100644 > --- a/docs/nvdimm.txt > +++ b/docs/nvdimm.txt > @@ -171,6 +171,32 @@ guest software that this vNVDIMM device contains a > region that cannot > accept persistent writes. In result, for example, the guest Linux > NVDIMM driver, marks such vNVDIMM device as read-only. > > +Backend File Setup Example > +..........................
For consistency with the rest of the document please use '-' instead of '.'. > + > +Here is two examples for how to setup these persistent backend on > +linux, which leverages the tool ndctl [3]. Small grammar tweaks: Here are two examples showing how to set up persistent backends on Linux using the tool ndctl [3]. > + > +It is easy to setup DAX device backend file. Please move this into the "A. DAX device" section and use it as an introduction to explain what this section is about: Use the following command to set up /dev/dax0.0 so that the entirety of namespace0.0 can be exposed as an emulated NVDIMM to the guest: > + > +A. DAX device > + > + ndctl create-namespace -f -e namespace0.0 -m devdax > + > +The /dev/dax0.0 could be used directly in "mem-path" option. > + > +For DAX file, it is more than creating the proper namespace. The > +block device should be partitioned and mounted (with dax option). Please move this into "B. DAX file": Individual files on a DAX host file system can be exposed as emulated NVDIMMS. First an fsdax block device is created, partitioned, and then mounted with the "dax" mount option: > + > +B. DAX file > + > + ndctl create-namespace -f -e namespace0.0 -m fsdax > + (partition /dev/pmem0 with name pmem0p1) > + mount -o dax /dev/pmem0p1 /mnt > + (dd a file with proper size in /mnt) "dd a file" could be "create or copy a disk image file with qemu-img(1), cp(1), or dd(1) in /mnt".
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