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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_ize(8)    The  NetWorker  installation  script.   The  script  will
		     install both clients and servers.	The nsr_ize script can
		     also be used to de-install	 NetWorker.   Note  that  some
		     systems   use   other  methods  for  installing  and  de-
		     installing NetWorker, in which case  the  nsr_ize	script
		     will not exist.

       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.

       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.

       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_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.

       nwbackup(8)  A  Motif-based  tool  for  backing up files.  The nwbackup
		    command is the graphical equivalent of save.

       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  pro‐
       cessing	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 opera‐
       tion commands include save, savefs, and recover.	 Both groups  of  com‐
       mands  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(1) 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),	 nwre‐
       cover(8), nsrclone(8),  nsrssc(8),  nsrmm(8),  mmpool(8),  mmlocate(8),
       nsrjb(8),  nsrinfo(8),  nsrstage(8),  nsrcap(8),	 save(8),  nsrpmig(8),
       nwbackup(8), nsrck(8), nsrim(8),	 jbconfig(8),  nsrcnct(8),  and	 scan‐
       ner(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
       authenticated only if a common name between the two lists exists.

       The NetWorker server maps a client's name to an on-line index  database
       name  by	 resolving  the client's name to the official name returned by
       gethostbyname.  This mapping takes place both at client	creation  time
       and at connection establishment time.

       To  ensure  safe	 and  effective	 naming, the following rules should be
       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), nwbackup(8), nwrecover(8),
       recover(8), mmrecov(8), save(8), savefs(8), savegrp(8), scanner(8),
       uasm(8).
       The NetWorker Administrator's Guide

NetWorker 7.3.2			  Aug 23, 06				NSR(8)
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