nsr(8)                                                                                     nsr(8)

NAME

       nsr - introduction and overview of NetWorker


DESCRIPTION

       NetWorker  facilitates the backup and recovery of files on a network of
       computer systems.  Files and filesystems may be backed up on  a  sched-
       uled basis.  Recovery of entire filesystems and single files is simpli-
       fied by use of an on-line index of saved files.

       NetWorker uses a client-server model to provide  the  file  backup  and
       recover  service.  At least one machine on the network is designated as
       the NetWorker server, and the machines with disks to be backed  up  are
       NetWorker clients.  Five daemons provide the NetWorker service, control
       access to the system, and provide index  and  media  support.   On  the
       clients, there are special programs to access the file systems and com-
       municate with the NetWorker server.

       The NetWorker system has several parts.  Commands and  files  are  only
       briefly  mentioned  here; see the appropriate reference manual page for
       more detailed information.  Each command has a  manual  page  entry  in
       section 8.  The files and their formats are explained in section 5 man-
       ual pages.

       The NetWorker Administrator's Guide provides information on configuring
       and  administering  a  NetWorker system.  It includes many examples and
       rationales for setting up and running a successful backup operation.


INSTALLATION

       How NetWorker is installed depends on the architecture of  the  machine
       upon which you are installing.  For detailed installation instructions,
       see the NetWorker Installation Guide for your specific platform.

       nsr_layout(5) Describes  where  NetWorker  programs,  files, and manual
                     pages are installed.


SERVER DAEMONS

       NetWorker uses a client-server model to provide a  backup  and  recover
       service.  The following daemons encompass the server side of NetWorker.

       nsrd(8)      The main NetWorker daemon.  nsrd handles initial  communi-
                    cation  with  clients, and starts and stops the other Net-
                    Worker server daemons.

       ansrd(8)     The agent nsrd process, spawned by nsrd in response  to  a
                    recovery,  clone,  or  other session.  The ansrd daemon is
                    invoked on an as-needed basis and  is  only  present  when
                    there are sessions active to the NetWorker server.  Modern
                    versions of save(8) do not require use of an ansrd daemon.
                    save sets and media.  The nsrmmdbd daemon provides a  much
                    coarser  view  of the saved files than does nsrindexd, and
                    therefore the resultant index is usually much smaller.
                    
       nsrindexd(8) This server daemon provides access to  the	NetWorker  on-
                    line  index.  The index holds records of saved files.  The
                    index allows clients  to  selectively  browse  and	choose
                    files  to  recover	without	 having	 to  access the backup
                    media.

       nsrmmdbd(8)  The media management database daemon provides an index  of
                    save  sets and media.  The nsrmmdbd daemon provides a much
                    coarser view of the saved files than does  nsrindexd,  and
                    therefore the resultant index is usually much smaller.

       nsrjobd(8)   The	 jobs  daemon  provides for the centralized monitoring
                    and control of remote execution "jobs", typically save and
                    directed  recover.	It manages the parallelism when spawn-
                    ing remote jobs and monitors the status for reporting  and
                    storing  execution information.  All scheduled backups are
                    initiated from nsrjobd.

       nsrmmd(8)    The media multiplexor daemon provides device  support  for
                    NetWorker.  When more than one client is saving files, the
                    data from each client  is  multiplexed.   During  recovery
                    operations, the data is demultiplexed and sent back to the
                    requesting  clients.   When  the  multiple   devices   are
                    enabled, several of these daemons may be active simultane-
                    ously.


ADMINISTRATION

       NetWorker is administered via resources and attributes.  Every resource
       has  one  or more attributes associated with it.  For example, a device
       is a NetWorker resource type; an attribute of  devices  is  the  device
       type,  for example, 4mm or 8mm.  The NetWorker resource format is docu-
       mented in nsr_resource(5).  There is also a manual page for  each  Net-
       Worker resource in section 5 of the manual.

       Resource  files  are  not normally edited by hand.  Rather, a NetWorker
       tool (usually NetWorker Management Console or nsradmin(8)) is  used  to
       modify  resource files  dynamically  so  that  values  can be checked
       and changes can be propagated automatically to the interested programs.
       The following are tools that are used to administer various aspects of
       NetWorker.

       NetWorker Management Console
		    Monitors  the  activity  of	 and   administers   NetWorker
		    servers.   NetWorker  Management  Console  is a Java based
		    application and is most users' primary interface  to  Net-
		    Worker.

       nsradmin(8)  A curses(3) based tool for the administration of NetWorker
                    servers.

       nsrwatch(8)  A curses(3) based  tool  to monitor the activity of Net-
                    Worker servers.

       nsrmm(8)     Media manager command.   The  nsrmm  command  is  used  to
                    label,  mount,  unmount,  delete and purge volumes.  Mount
                    requests are generated by nsrmmd, and displayed by Net-
		    Worker Management Console or nsrwatch.   The  size of the 
		    on-line user file indexes may be controlled by deleting 
		    and purging volumes.

       nsrjb(8)     The NetWorker jukebox-controlling command.   When  dealing
                    with  a  jukebox, nsrjb, rather than nsrmm, should be used
                    to label, load, and unload the volumes contained within  a
                    jukebox.

       nsrim(8)     Automatically  manages  the  on-line index.  It is usually
                    run periodically by savegrp.

       mminfo(8)    Provides information about volumes and save sets.

       nsrck(8)     Checks and repairs the NetWorker on-line index.  It is run
                    automatically  when  nsrd  starts up if the databases were
                    not closed cleanly due to a system crash.
                    
       nsr_render_log(8)
                    Creates a human readable version of the Networker logs.

       nsr_shutdown(8)
                    A shell script used to safely shut	down  the  local  Net-
                    Worker server.  The nsr_shutdown script can only be run by
                    the super user.

SAVING FILES

       NetWorker supports both	scheduled  and	manual	saving	of  files  and
       filesystems.   Each  client may be scheduled to save all or part of its
       filesystems.  Different clients may be scheduled	 to  begin  saving  at
       different times.
       
       save(8)      A command-line-based tool used to back up a specified file
                    or group of files.  The save command may be  run  manually
                    by  users and administrators, or automatically by savegrp.

       savegrp(8)   Used to initiate the backup of a group of client machines.
                    Usually started automatically  by  the  NetWorker  server.
                    The  savegrp  command  also  backs up the clients' on-line
                    file indexes, which are stored on the server.  When  back-
                    ing  up  the  server  itself, a bootstrap save set is also
                    created.

       nsrexec(8)   The  agent  savegrp  process,  spawned  by  savegrp.   The
                    nsrexec  command  monitors  the progress of NetWorker com-
                    mands.

       nsrclone(8)  The NetWorker save set/volume cloning command.  Using nsr-
                    clone,  clones,  or exact replicas, of save sets or entire
                    volumes can be made.  Clone data is indistinguishable from
                    the  original data, except for the NetWorker media volumes
                    upon which the data reside.

       nsrexecd(8)  NetWorker-specific remote execution service which runs  on
                    NetWorker  clients.   Used  by  savegrp  to start save and
                    savefs on client machines.

       savefs(8)    Used by savegrp to determine characteristics of a  client,
                    and  to  map  the  save set All to the current list of all
                    save sets on a client.


RECOVERING FILES

       NetWorker maintains an on-line index  of  user  files  that  have  been
       saved.  Users may browse the index and select files for recovery.  This
       information is used to build a representation of the file heirarchy  as
       of any time in the past.  NetWorker then locates the correct volume and
       recovers the requested files.

       recover(8)   Browses the on-line user file index and selects files  and
                    filesystems to recover.

       nwrecover(8) A  Motif-based  tool  for recovering files.  The nwrecover
                    command is the graphical equivalent of recover.

       mmrecov(8)   Used only for disaster  recovery.   Recovers  the  special
                    bootstrap  index and the server's on-line file index.  The
                    recover or nwrecover commands are used  to  recover  other
                    on-line file indexes.

       scanner(8)   Verifies  correctness  and integrity of NetWorker volumes.
                    Can also recover complete save sets and  rebuild  the  on-
                    line file and media indexes.

       nsr_crash(8) A man page describing crash recovery techniques.
       
       nsrinfo(8)   Used to generate reports about the contents of a  client's
		    file index.
		    

APPLICATION SPECIFIC MODULES

       In order to process user files in an optimal manner, NetWorker provides
       the ASM mechanism.  Pattern  matching  is  used	to  select  files  for
       processing by the different ASMs.  The patterns and associated ASMs are
       described in nsr(5).  The save command keeps track of which  ASMs  were
       used to process a file so that recover may use the same ASMs to recover
       the file.

       uasm(8)        UNIX  filesystem specific save/recover module.  The uasm
                      man page documents the general rules for all ASMs.   The
                      uasm  command and its man page actually comprise several
                      additional ASMs,  including  compressasm,  mailasm,  and
                      xlateasm, to name a few.

       nsrindexasm(8) Processes the on-line user file indexes.

       nsrmmdbasm(8)  Processes the on on-line media database.


SERVER LOCATION

       On  large  networks  there  may be several NetWorker servers installed.
       Each NetWorker client command must select a server to use.

       For server selection, the  client  commands  are  classified  into  two
       groups:  administration  and  operation.   The  administration commands
       include NetWorker Management Console, nsrwatch, and mminfo.
       The operation commands  include save,  savefs, and recover.  Both groups
       of commands accept a -s server option to explicitly specify a NetWorker
       server.

       When a server is not explicitly specified, the operation  commands  use
       the following steps to locate one.  The first server found is used.

       1)   The  local machine is examined to see if it is a NetWorker server.
            If it is, then it is used.

       2)   The machine where the current directory  is  actually  located  is
            examined to see if it is a NetWorker server.  If it is, then it is
            used.

       3)   The machine specified with the -c option is examined to see if  it
            is a NetWorker server.  If it is, then it is used.

       4)   The  list  of trusted NetWorker servers is obtained from the local
            machine's nsrexecd(8).  Each machine on the list  is  examined  to
            see  if it is a NetWorker server.  The first machine determined to
            be a NetWorker server is used.

       5)   A broadcast request is issued.   The  first  NetWorker  server  to
            respond to the request is used.

       6)   If  a  NetWorker  server  still has not been found, then the local
            machine is used.

       The administrative commands only use step 1.


SECURITY

       Before a save is allowed, there must be an NSR client resource  created
       for  the  given client.  Before a recovery is allowed, the server vali-
       dates client access by checking the remote access attribute in the  NSR
       client resource (see nsr_client(5)).

       The  savegrp(8)  command  initiates  the save(8) command on each client
       machine in an NSR group by using the nsrexecd(8) remote save  execution
       service.   See the nsrexecd(8) man page for details.  For backward com-
       patibility with older versions of NetWorker, savegrp(8). will fall  back
       on  using  the  rsh(8) protocol for remote execution if nsrexecd is not
       running on a particular client.

       Access to the NSR resources through the	nsradmin(8)  command  or  Net-
       Worker  Management Console is controlled by the administrator attribute
       on the NSR server resource (see nsr_service(5)).	 This attribute has  a
       list  of	 names	of  the	 users	who have permission to administer that
       resources.  Names that begin with an ampersand (&) denote netgroups (see
       netgroup(5)).   Also names  can be of the form user@host or
       user=user,host=host to authorize a specific user on a specific host.


ROOT PRIVILEGES

       The system administrator can grant root privileges to  specific  groups
       of users by changing the mode of a NetWorker program to setuid-root and
       setgid-group.  (See chgrp(1) and chmod(1) for more details.)

       When a user invokes a program that  is  both  setuid-root  and  setgid-
       group, he may retain root privileges if one of the following is true:

       1.     The user's name and the program's group name are identical.

       2.     One  of  the process's supplementary group id names is identical
              to  the  program's  group  name.   (See  getgroups(2)  for  more
              details.)

       3.     The  user's  name  is  an  element of the netgroup whose name is
              identical to the program's group  name.   (See  getgrnam(3)  for
              more details.)

       For  example,  the  mode  and group owner of the recover command can be
       changed such that the ls output looks like:
              -rws--s--x  1 root  staff  548808 Apr 18 16:04 recover
       A user invoking this command will retain root  privileges  if  (1)  his
       name is 'staff', or (2) he is a member of the group 'staff', or (3)
       his name appears as an element of the netgroup 'staff'.

       Granting root privileges may be applied to the following NetWorker pro-
       grams: nsrexec(8), nsrports(8), recover(8), nwretrieve(8), nwrecover(8),
       nsrclone(8), nsrconsolidate(8), nsrmm(8), mmpool(8), mmlocate(8),
       nsrjb(8), nsrinfo(8), nsrstage(8), nsrcap(8), save(8), nsrpmig(8), 
       nsrck(8), nsrim(8), jbconfig(8), nsrcnct(8), and scanner(8).


NAMING AND AUTHENTICATION

       As  described  above, the NSR server only accepts connections initiated
       from the machines listed as clients or listed in the remote access list
       (for  recovering).   Since  machines  may be connected to more than one
       physical network and since each physical network  connection  may  have
       numerous  aliases,  the policies below are used as a compromise between
       security and ease of use.  For further information about naming in  the
       UNIX environment, refer to gethostent(3) or other documentation on name
       services.

       A client determines its own name as follows.  First the  client's  UNIX
       system  name  is acquired via the gethostname(2) system call.  The UNIX
       system name is used as a parameter to the gethostbyname(3) library rou-
       tine.  The client declares its name to be the official (or 'primary')
       name returned by gethostbyname.  This name is passed to  the  NetWorker
       server during connection establishment.

       A  server  authenticates a client connection by reconciling the connec-
       tion's remote address with client's stated name.  The address is mapped
       to  a  list  of  host  names via the gethostbyaddr(3) library function.
       Next, the client's stated name is used as a parameter to  gethostbyname
       to  acquire  another  list  of  host names.  The client is successfully
       employed:

       1)   The NetWorker clients and servers should  access  consistent  host
            name  databases.   NIS  (YP)  and the Domain Name System (DNS) are
            naming subsystems that aid in host name consistency.

       2)   All hosts entries for a single machine should have  at  least  one
            common alias among them.

       3)   When creating a new client, use a name or alias that will map back
            to the same official name that  the  client  machine  produces  by
            backward mapping its UNIX system name.


SEE ALSO

       rsh(1), gethostname(2), gethostent(3), netgroup(5), nsr(5),
       nsr_layout(5), nsr_resource(5), ypfiles(5), ypmake(5), mminfo(8),
       nsr_crash(8), nsr_ize(8), nsr_service(5), nsr_shutdown(8), nsradmin(8),
       nsrck(8), nsrclone(8), nsrd(8), nsrexecd(8), nsrim(8), nsrindexasm(8),
       nsrindexd(8), nsrinfo(8), nsrjb(8), nsrls(8), nsrmm(8), nsrmmd(8),
       nsrmmdbasm(8), nsrmmdbd(8), nsrwatch(8), nwadmin(8), nwbackup(8),
       nwrecover(8), recover(8), mmrecov(8), save(81), savefs(8), savegrp(8),
       scanner(8), uasm(8). and The NetWorker Administrator's Guide

NetWorker 8.0.1 		Dec 02, 12 			nsr(8)