On Wed, Jul 24, 2019 at 06:17:31AM -0400, Pankaj Gupta 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 >> +.......................... >> + >> +Here is two examples for how to setup these persistent backend on >> +linux, which leverages the tool ndctl [3]. >> + >> +It is easy to setup DAX device backend file. >> + >> +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). >> + >> +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) > >This is not clear to me. why 'dd' file is required in /mnt? >You mean for creating a backend file? >
Yes, create a backend file. You need to give a file instead of a directory to qemu command line. >> + >> +Then the new file in /mnt could be used in "mem-path" option. >> + >> NVDIMM Persistence >> ------------------ >> >> @@ -212,3 +238,5 @@ References >> >> https://www.snia.org/sites/default/files/technical_work/final/NVMProgrammingModel_v1.2.pdf >> [2] Persistent Memory Development Kit (PMDK), formerly known as NVML >> project, home page: >> http://pmem.io/pmdk/ >> +[3] ndctl-create-namespace - provision or reconfigure a namespace >> + http://pmem.io/ndctl/ndctl-create-namespace.html >> -- > >Looks good to me. Just a small comment above. >Other than that: Reviewed-by: Pankaj Gupta <pagu...@redhat.com> > Thanks >> 2.17.1 >> >> >> -- Wei Yang Help you, Help me
