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NAME

       rpmemd - librpmem target node process (DEPRECATED)

SYNOPSIS

              $ rpmemd [--help] [--version] [<args>]

DESCRIPTION

       The  rpmemd  process  is  executed  on  target node by librpmem(7) library over ssh(1) and
       facilitates access to persistent memory over RDMA.  The rpmemd should not be run  manually
       under normal conditions.

OPTIONS

       Command  line options overwrite the default rpmemd configuration, the global configuration
       file and the user configuration file.

       -V, --version

       Displays rpmemd version and exits.

       -h, --help

       Prints synopsis and list of parameters and exits.

       -c, --config <path>

       Custom configuration file location.  If the custom configuration file is  provided  others
       are omitted.  See CONFIGURATION FILES section for details.

       All options described in CONFIGURATION FILES section are common for both the configuration
       file and the command line - the equivalent of the following line in the config file:

       option = value

       is

       --option value

       in the command line.

       The following command line options: –persist-apm, –persist-general and –use-syslog  should
       not  be  followed  by any value.  Presence of each of them in the command line turns on an
       appropriate option.  See CONFIGURATION FILES section for details.

       -r, --remove <poolset>

       Remove a pool described by given pool set file descriptor.  It is interpreted as a path to
       the pool set file relative to the pool set directory.

       -f, --force

       Ignore errors when removing a pool file using –remove option.

CONFIGURATION FILES

       The rpmemd searches for the configuration files with following priorities:

       • The global configuration file located in /etc/rpmemd/rpmemd.conf.

       • The user configuration file located in the user home directory ($HOME/.rpmemd.conf).

       The  rpmemd  can also read configuration from the custom configuration file provided using
       –config command line option.  See OPTIONS section for details.

       The default configuration is described in the DEFAULT CONFIGURATION section.

       The configuration file is a plain text file.  Each line  of  the  configuration  file  can
       store  only  one  configuration option defined as a key=value pair.  Empty lines and lines
       starting with # are omitted.

       The allowed options are:

       • log-file = <path> - log file location

       • poolset-dir = <path> - pool set files directory

       • persist-apm = {yes|no} - enable The Appliance Persistency Method.  This option  must  be
         set  only  if the target platform has non-allocating writes IO enabled.  See PERSISTENCY
         METHODS section for details.

       • persist-general = {yes|no} - enable The General Purpose Server Persistency Method.   See
         PERSISTENCY METHODS section for details.

       • use-syslog = {yes|no} - use syslog(3) for logging messages instead of log file

       • log-level = <level> - set log level value.  Accepted <level> values are:

         • err - error conditions

         • warn - warning conditions

         • notice - normal, but significant conditions

         • info - informational message

         • debug - debug-level message

       The  $HOME  sub-string  in  the  poolset-dir  path  is replaced with the current user home
       directory.

EXAMPLE

       Example of the configuration file:

              # This is an example of configuration file
              log-file = $HOME/.logs/rpmemd.log
              poolset-dir = $HOME/poolsets/
              persist-apm = yes
              persist-general = no
              use-syslog = no # Use log file instead of syslog
              log-level = info

DEFAULT CONFIGURATION

       The rpmemd default configuration is equivalent of the following configuration file:

              log-file = /var/log/rpmemd.log
              poolset-dir = $HOME
              persist-apm = no
              persist-general = yes
              use-syslog = yes
              log-level = err

PERSISTENCY METHODS

       The librpmem(7) supports two methods for making data written to remote  persistent  memory
       durable.   The  difference  between  the  use  of  the  two mechanisms is based on whether
       librpmem(7) will make use of non-allocating writes on the remote node.

       • The General Purpose Server Persistency Method does not have  any  requirements  for  the
         platform  on  which the target daemon runs and can be enabled by administrator using the
         persist-general option.  This method utilize libpmem(7) persistency mechanisms on remote
         node  and  requires additional communication between initiator and remote node using the
         in-band connection.

       • The Appliance Persistency Method requires non-allocating writes enabled on the  platform
         and  can  be enabled by administrator using persist-apm option.  This method requires to
         issue an RDMA READ operation after the RDMA  WRITE  operations  performed  on  requested
         chunk of memory.

       “Non-allocating  write  requests”  is  the  Intel  Integrated IO Controller mode where all
       incoming  PCIe  writes  will  utilize  non-allocating  buffers  for  the  write  requests.
       Non-allocating  writes  are guaranteed to bypass all of the CPU caches and force the write
       requests to flow directly to the Integrated Memory Controller without delay.

       The rpmemd dynamically choose the appropriate  persistency  method  and  the  flushing  to
       persistence  primitive  for  GPSPM  for  each  opened pool set name depending on available
       persistency methods and whether all pool set parts are stored in the persistent memory.

       If the Appliance Persistency Method  is  enabled  and  the  pool  set  is  stored  in  the
       persistent  memory  rpmemd  will use the Appliance Persistency Method.  If the pool set is
       NOT stored in the persistent memory it  will  fallback  to  the  General  Puropose  Server
       Persistency Method with pmem_msync(3).

       If the General Puropose Server Persistency Method is enabled and the pool set is stored in
       the persistent memory rpmemd will use pmem_persist(3).  If the pool set is NOT  stored  in
       the persistent momory it will use pmem_msync(3).

       See pmem_persist(3) and pmem_msync(3) for more details.

NOTE

       The  librpmem(7)  library  and  rpmemd  is deprecated since PMDK 1.12 release.  If you are
       interested in a  remote  persistent  memory  support  please  look  at  new  library  rpma
       https://github.com/pmem/rpma.

SEE ALSO

       ssh(1),  pmem_msync(3), pmem_persist(3), syslog(3), libpmem(7), libpmemobj(7), librpmem(7)
       and <https://pmem.io>