Norbert Gruener > AFS-2.6.3 > AFS::VLDB

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Module Version: v2.6.3   Source  

NAME ^

AFS::VLDB - Class to communicate with the AFS Volume Location Server

SYNOPSIS ^

  use AFS::VLDB;

  my $vldb = AFS::VLDB->new(1, 120, 1);
  $vol->DESTROY;

  $vldb = AFS::VLDB->new;
  my $ok = $vldb->addsite('server2', 'vicepa', 'volume');
  $ok = $vldb->remsite('server1', '/vicepa', 'volume');

  $ok = $vos->changeloc('volume', 'server2', '/vicepb');

  $ok = $vldb->removeaddr('192.168.18.25');

  my ($succ, $fail) = $vldb->delentry(['volume', 'volume.projects']);
  ($succ, $fail) = $vldb->delentry('volume');
  ($succ, $fail) = $vldb->delgroups('home', 'server', '/vicepa', 1);

  my @addrlist = $vldb->listaddrs('', '', 0, 1);

  my $vldblist = $vldb->listvldb('server1', '/vicepa');
  my $vldblist = $vldb->listvldbentry('root.afs');

  $ok = $vldb->lock('volume');
  $ok = $vldb->unlock('volume');
  $ok = $vldb->unlockvldb('server1', '/vicepa');

  $ok = $vldb->syncserv('server1', '/vicepa');
  $ok = $vldb->syncvldb('server1', '/vicepa');
  $ok = $vldb->syncvldbentry('volume');

DESCRIPTION ^

This class is used to communicate with the AFS Volume Location Server in order to maintain and to administer the Volume Location Database (VLDB) maintained by the Volume Location Server. The VLDB is used to allow AFS application programs to discover the location of any volume within its cell, along with select information about the nature and state of that volume. This class provides methods to lookup for volumes or to lock/unlock them in the DB. It is used to remove and to list DB entries, and to synchronize the VLDB against the AFS partitions.

Before you can access any VLDB records you must establish a connection to the Volume Location Server. This is done by the constructor method new which returns a VLDB object. A VLDB object is essentially a handle to talk to the Volume Location Server in a given cell. Such a VLDB object is required before any of the other VLDB instance methods can be called.

COMPATIBILITY ^

There was no version 1 implementation and hence there are no version conflicts :-)

METHODS ^

CONSTRUCTOR
 
$vldb = AFS::VLDB->new([VERBOSE [, TIMEOUT [, NOAUTH [, LOCALAUTH [, CELL [, ENCRYPT]]]]]);

Creates a new object of the class AFS::VLDB. An AFS::VLDB object is essentially a handle to talk to the Volume Location Server. Internally an AFS::VLDB object is a pointer to a ubik_client structure, although this may change and the value returned from AFS::VLDB::new should always be treaded as an opaque handle.

Set VERBOSE (default 0) to 1 to produce on the standard output stream a detailed trace of the method's execution. TIMEOUT is the time of inactivity in seconds before the connection to the VLDB server is declared dead (default 90 seconds). Set LOCALAUTH (default 0) to 1 only when issuing a command on a server machine. If NOAUTH is 1 (default 0) it establishes an unauthenticated connection to the server, in which the servers treat the issuer as an unprivileged user. CELL (default NULL) specifies the cell in which to run the command. Set ENCRYPT to 1 (default 0) to encrypt the connection to the VLDB server.

DESTRUCTOR
 
$vldb->DESTROY;

Destroys the ubik connection to the Volume Location Server and frees the ubik_client structure.

INSTANCE METHODS
 
$ok = $vldb->addsite(SERVER, PARTITION, VOLUME [, ROVOL, VALID]);

Defines a new read-only site specified by the SERVER and PARTITION arguments, in the Volume Location Database (VLDB) entry of the read/write VOLUME (volume name or volume ID number). ROVOL specifies either the complete name or volume ID number of the readonly volume. This will only be honored if the source read/write volume does not already have a readonly volume ID associated with it. If the source read/write volume already has a readonly volume ID, the specified ID will be ignored, and a warning will be printed. If this is not specified and the source read/write volume does not already have a readonly volume ID, a volume ID for the readonly volume will be allocated for it when the vos-release> method is run. The automatically allocated readonly volume IDs should be fine for almost all cases, so you should almost never need to specify this argument. This argument is supported when the AFS Perl modules are linked with the OpenAFS system libraries v1.4.12 or later. The VALID flag marks the site as up-to-date in the VLDB. You should only do this if the new site already has a current readonly replica of the volume, but for some reason it is not in the VLDB as a replica site. This is useful when an existing read-only volume is dumped and restored with the -readonly flag at the new site. This argument is supported when the AFS Perl modules are linked with the OpenAFS system libraries v1.4.7 or later.

It calls the AFS system library function UV_AddSite or UV_AddSite2 (OpenAFS v.1.4.12 or later).

$ok = $vldb->changeloc(VOLUME, SERVER, PARTITION);

Changes the location of the read/write VOLUME (volume name or volume ID number) in the VLDB to SERVER and PARTITION. This method is only available with OpenAFS. It calls the AFS system library function UV_ChangeLocation.

($succ, $fail) = $vldb->delentry(VOLUME [, NOEXECUTE]);
($succ, $fail) = $vldb->delentry(\@VOLUME [, NOEXECUTE]);

Removes the VLDB entry for each specified VOLUME. VOLUME is either a scalar value or a reference to an array of volume names or of volume ids. If you set NOEXECUTE to 1 (default 0) then the volume name is just printed but NOT deleted. It returns the number of successfully deleted volumes and the number of failed volumes. It calls the AFS system library function VL_DeleteEntry.

Cautions

Do not use this method to remove a volume in normal circumstances; it does not remove a volume from the file server machine, and so is likely to make the VLDB inconsistent with state of the volumes on server machines. Use the AFS::VOS remove method to remove both the volume and its VLDB entry.

($succ, $fail) = $vldb->delgroups(PREFIX, SERVER, PARTITION [, NOEXECUTE]);

Removes the VLDB entries for groups of volumes. PREFIX specifies a certain character string for the beginning of the volume name. SERVER specifies the file server machine and PARTITION specifies the partition name where the volumes where sitting. If you specify an empty string for either PREFIX, SERVER, or PARTITION it is considered as a wild card option for this argument. If you set NOEXECUTE to 1 (default 0) then the volume name is just printed but NOT deleted. It returns the number of successfully deleted volumes and the number of failed volumes. It calls the AFS system library function VL_DeleteEntry.

Cautions

Do not use this method to remove a volume in normal circumstances; it does not remove a volume from the file server machine, and so is likely to make the VLDB inconsistent with state of the volumes on server machines. Use the AFS::VOS remove method to remove both the volume and its VLDB entry.

@addrlist = $vldb->listaddrs([HOST [, UUID [, NORESOLVE [, PRINTUUID]]]]);

Returns all server entries from the VLDB. An entry is created as the File Server initializes and registers the contents of its local sysid file in the VLDB. The return value is an array of hashes. If you specify HOST or UUID only the entry for this HOST or UUID is returned. If you set NORESOLVE (default 0) to 1, only the IP address is returned. If you set PRINTUUID (default 0) to 1, the UUID (AFS' internal host representation) for each server is also returned.

It calls the AFS system library function VL_GetAddrs or VL_GetAddrsU.

Important Hint

In version 2.4.1 the hash key names for "NAME" and "IP" have changed. The new names are now "NAME-x" and "IP-x" where "x" is {1,2,3,...}.

You can find an example how to print the entire content of returned array of hashes in the examples/v2/vldb directory.

$vldblist = $vldb->listvldb([SERVER [, PARTITION [, LOCK]]]);

Returns information from the Volume Location Database (VLDB) entry for each volume specified. The return value is a reference to a hash table containing the values from the C structure nvldbentry. The actual information returned depends on the combination of arguments supplied when the method is applied. Combine the arguments as indicated:

 * Every entry in the VLDB: provide no arguments.

 * Every VLDB entry that mentions a certain file server
   machine as the site for a volume: specify the SERVER argument.

 * Every VLDB entry that mentions a certain partition on any
   file server machine as the site for a volume: specify the
   PARTITION argument.

 * Every VLDB entry that mentions a certain partition on a
   certain file server machine as the site for a volume:
   combine the SERVER and PARTITION arguments.

If you set LOCK (default 0) to 1 it returns only locked VLDB entries. This flag can be combined with the SERVER argument, the PARTITION argument, or both.

It calls the AFS system library function VolumeInfoCmd.

You can find an example how to print the entire content of the returned hash reference in the examples/v2/vldb directory.

$vldblist = $vldb->listvldbentry(VOLUME);

Returns information from the Volume Location Database (VLDB) entry for the specified VOLUME (volume name or volume ID number). The return value is a reference to a hash table containing the values from the C structure nvldbentry.

It calls the AFS system library function VolumeInfoCmd.

You can find an example how to print the entire content of the returned hash reference in the examples/v2/vldb directory.

$ok = $vldb->lock(VOLUME);

Locks the VLDB entry for VOLUME (volume name or volume ID number), blocking any operation that requires a write to that entry. The lock applies to all of the volume versions associated with the entry, not just the one specified. It calls the AFS system library function VL_SetLock.

$ok = $vldb->removeaddr(IP);

Removes from the VLDB the server entry that includes the address specified by the IP argument. It calls the AFS system library function VL_ChangeAddr.

$ok = $vldb->remsite(SERVER, PARTITION, VOLUME);

Removes the read-only replication site specified by the SERVER and PARTITION arguments from the Volume Location Database (VLDB) entry for the indicated read/write VOLUME.

This method is useful for removing read-only sites that were mistakenly created with the addsite method, before the volume was actually released. If a read-only copy already exists at the site, it is not affected. However, if this read-only site was the last site housing any version of the volume, then the entire VLDB entry is removed, even if a copy of the read-only version still actually exists at the site.It calls the AFS system library function UV_RemoveSite.

$ok = $vldb->syncserv(SERVER [, PARTITION]);

Verifies that each volume mentioned in a VLDB entry actually exists at the site indicated in the entry. It checks all VLDB entries that mention a read/write, read-only, or backup site either on any partition on the file server machine specified by the SERVER argument, or on the one partition specified by the SERVER and PARTITION arguments. It calls the AFS system library function UV_SyncServer.

$ok = $vldb->syncvldb(SERVER [, PARTITION]);

Verifies that the status of the volumes housed either on all partitions on the file server machine specified by the SERVER argument, or on the single partition specified by the SERVER and PARTITION arguments, is recorded correctly in the VLDB. It calls the AFS system library function UV_SyncVolume.

$ok = $vldb->syncvldbentry(VOLUME);

Verifies that the status of the VOLUME is recorded correctly in the VLDB. It calls the AFS system library function UV_SyncVolume.

$ok = $vldb->unlock(VOLUME);

Releases the lock on the VLDB entry for the specified VOLUME (volume name or volume ID number). It calls the AFS system library function UV_LockRelease.

$ok = $vldb->unlockvldb([SERVER [, PARTITION]]);

Releases the lock on the VLDB entries indicated by the combination of arguments provided:

  * To unlock all entries in the VLDB, provide no arguments.

  * To unlock all entries that mention a file server machine
    in a site definition, provide its name with the SERVER
    argument.

  * To unlock all entries that mention a partition on any
    file server machine in a site definition, provide the
    partition name with the PARTITION argument.

  * To unlock all entries that mention a specific site,
    provide both the SERVER and PARTITION arguments.

It calls the AFS system library function VL_ReleaseLock.

AUTHORS ^

The code and documentation for this class were contributed by Stanford Linear Accelerator Center, a department of Stanford University. This documentation were written by

Alf Wachsmann <alfw@slac.stanford.edu>, and
Norbert E. Gruener <nog@MPA-Garching.MPG.de>
 

COPYRIGHT AND DISCLAIMER ^

 Copyright (c) 2005-2011 Norbert E. Gruener <nog@MPA-Garching.MPG.de>
 Copyright (c) 2003-2004 Alf Wachsmann <alfw@slac.stanford.edu> and
                         Norbert E. Gruener <nog@MPA-Garching.MPG.de>
 All rights reserved.

Most of the explanations in this document are taken from the original AFS documentation.

 AFS-3 Programmer's Reference:
 Volume Server/Volume Location Server Interface
 Edward R. Zayas
 Copyright (c) 1991 Transarc Corporation.
 All rights reserved.

 IBM AFS Administration Reference
 Copyright (c) IBM Corporation 2000.
 All rights reserved.

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

DOCUMENT VERSION ^

Revision $Rev: 1078 $

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