db_hotbackup(category8-imap.html) - phpMan

DB_HOTBACKUP(1)              BerkeleyDB Utilities              DB_HOTBACKUP(1)

NAME
       db_hotbackup - Create "hot backup" or "hot failover" snapshots
SYNOPSIS
       db_hotbackup  [-cDEguVv]  [-d  data_dir ...] [-h home] [-l log_dir] [-P
       password] -b backup_dir
DESCRIPTION
       The db_hotbackup utility creates "hot backup" or "hot  failover"  snap-
       shots of Berkeley DB database environments.
       The db_hotbackup utility performs the following steps:
              1. Sets  the  DB_HOTBACKUP_IN_PROGRESS flag in the home database
                 environment.
              2. If the -c option is specified,  checkpoint  the  source  home
                 database environment, and remove any unnecessary log files.
              3. If  the target directory for the backup does not exist, it is
                 created with mode read-write-execute for the owner.
                 If the target directory for the backup does exist and the  -u
                 option  was  specified, all log files in the target directory
                 are removed; if the -u option was not specified, all files in
                 the target directory are removed.
              4. If the -u option was not specified, copy application-specific
                 files found in the database environment  home  directory,  or
                 any  directory specified using the -d option, into the target
                 directory for the backup.
              5. Copy all log files found in the directory specified by the -l
                 option  (or in the database environment home directory, if no
                 -l option was specified), into the target directory  for  the
                 backup.
              6. Perform catastrophic recovery on the hot backup.
              7. Remove any unnecessary log files from the hot backup.
              8. Reset the DB_HOTBACKUP_IN_PROGRESS flag in the environment.
       The db_hotbackup utility does not resolve pending transactions that are
       in the prepared state. Applications  that  use  DB_TXN->prepare  should
       specify   DB_RECOVER_FATAL   when  opening  the  environment,  and  run
       DB_ENV->txn_recover to resolve any pending transactions,  when  failing
       over to the hot backup.
OPTIONS
       -b backup_dir
              Specify the target directory for the backup.
       -c     Before  performing  the snapshot, checkpoint the source database
              environment and remove any log files that are no longer required
              in  that  environment.   To  avoid  making  catastrophic failure
              impossible, log file removal must be integrated  with  log  file
              archival.
              Care  should be taken with the -c option, where the db_hotbackup
              MUST be run by the same user that owns the database. If  db_hot-
              backup  is run by a user different to the owner of the database,
              a new log file owned by this user might be  created,  making  it
              impossible to use the database for its owner.
       -D     Use  the data and log directories listed in a DB_CONFIG configu-
              ration file in  the  source  directory.  This  option  has  four
              effects:
              1. The  specified data and log directories will be created rela-
                 tive to the target directory,  with  mode  read-write-execute
                 owner, if they do not already exist.
              2. In  step  #3  above, all files in any source data directories
                 specified in the DB_CONFIG file will be copied to the  target
                 data directories.
              3. In  step  #4  above,  log  files  will be copied from any log
                 directory specified in the DB_CONFIG file,  instead  of  from
                 the default locations.
              4. The  DB_CONFIG  configuration  file  will  be copied from the
                 source directory to the target  directory,  and  subsequently
                 used  for  configuration  if  recovery  is  run in the target
                 directory.
              Care should be taken with the  -D  option  where  data  and  log
              directories  are  named relative to the source directory but are
              not subdirectories (that is, the name includes the element "..")
              Specifically,  the  constructed  target  directory names must be
              meaningful and distinct from the source directory names,  other-
              wise  running recovery in the target directory might corrupt the
              source data files.
              It is an error to use absolute pathnames for data or log  direc-
              tories  in this mode, as the DB_CONFIG configuration file copied
              into the target directory would then point at the source  direc-
              tories and running recovery would corrupt the source data files.
       -d data_dir
              Specify  one  or more source directories that contain databases;
              if none is specified, the database  environment  home  directory
              will  be  searched  for  database  files.  As database files are
              copied into a single backup directory,  files  named  the  same,
              stored  in  different  source  directories, could overwrite each
              other when copied into the backup directory.
       -F     Directly copy from the filesystem. This option can  CORRUPT  the
              backup if used while the environment is active and the operating
              system does not support atomic file system reads.   This  option
              is  known  to be safe only on UNIX systems, not Linux or Windows
              systems.
       -h home
              Specify the source directory for the backup, that is, the  data-
              base environment home directory.
       -l log_dir
              Specify  a  source directory that contains log files; if none is
              specified, the  database  environment  home  directory  will  be
              searched for log files.
       -P password
              Specify an environment password.  Although Berkeley DB utilities
              overwrite password strings as soon as possible, be  aware  there
              may  be  a window of vulnerability on systems where unprivileged
              users can see command-line arguments or where utilities are  not
              able  to  overwrite the memory containing the command-line argu-
              ments.
       -u     Update a pre-existing hot backup snapshot by copying in new  log
              files.   If  the  -u  option  is specified, no databases will be
              copied into the target directory.
       -V     Write the library version number to  the  standard  output,  and
              exit.
       -v     Run in verbose mode, listing operations as they are done.
       -D     Use  the  data directories listed in the DB_CONFIG configuration
              file in the source directory.   This option has  three  effects:
              First, if they do not already exist, the specified data directo-
              ries will be created relative to the target directory (with mode
              read-write-execute  owner). Second, all files in the source data
              directories will be copied to the target data  directories.   If
              the  DB_CONFIG  file  specifies  one or more absolute pathnames,
              files in those source directories will be  copied  to  the  top-
              level  target directory. Third, the DB_CONFIG configuration file
              will be copied from the +source directory to the  target  direc-
              tory, and subsequently used for configuration if recovery is run
              in the target directory.
       Care should be taken with the -D option and data directories which  are
       named relative to the source directory but are not subdirectories (that
       is, the name includes the element "..")  Specifically, the  constructed
       target  directory names must be meaningful and distinct from the source
       directory names, otherwise running recovery  in  the  target  directory
       might corrupt the source data files.
       It  is  an  error to use absolute pathnames for data directories or the
       log directory in this mode, as the DB_CONFIG configuration file  copied
       into  the  target  directory would then point at the source directories
       and running recovery would corrupt the source data files.
       The db_hotbackup utility uses a Berkeley DB environment  (as  described
       for  the  -h  option,  the environment variable DB_HOME, or because the
       utility was run in a directory containing a Berkeley  DB  environment).
       In order to avoid environment corruption when using a Berkeley DB envi-
       ronment, db_hotbackup should always be given the chance to detach  from
       the  environment and exit gracefully.  To cause db_hotbackup to release
       all environment resources and exit cleanly, send it an interrupt signal
       (SIGINT).
EXIT STATUS
       The db_hotbackup utility exits 0 on success, and >0 if an error occurs.
ENVIRONMENT
       DB_HOME
              If  the  -h option is not specified and the environment variable
              DB_HOME is set, it is used as the path of the database home,  as
              described in DB_ENV->open.
SEE ALSO
       db_archive(1)  db_checkpoint(1)  db_deadlock(1)  db_dump(1) db_log_ver-
       ify(1)   db_load(1)   db_printlog(1)   db_recover(1)    db_replicate(1)
       db_stat(1) db_tuner(1) db_upgrade(1) db_verify(1)

BerkeleyDB 5.3.21              06 December 2016                DB_HOTBACKUP(1)