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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" snapshots 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 speci-
fied, 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_hotbackup 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 configuration file in the
source directory. This option has four effects:
1. The specified data and log directories will be created relative 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, otherwise running
recovery in the target directory might corrupt the source data files.
It is an error to use absolute pathnames for data or log directories 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.
-d data_dir
Specify one or more source directories that contain databases; if none is speci-
fied, 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 database environment home
directory.
-l log_dir
Specify a source directory that contains log files; if none is specified, the data-
base 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 arguments.
-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 directories will be created relative to the target directory
(with mode read-write-execute owner). Second, all files in the source data directo-
ries will be copied to the target data directories. If the DB_CONFIG file speci-
fies 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 directory, 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 dis-
tinct 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 Berke-
ley DB environment, 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_verify(1) db_load(1)
db_printlog(1) db_recover(1) db_replicate(1) db_stat(1) db_tuner(1) db_upgrade(1) db_ver-
ify(1)
BerkeleyDB 5.3.21 06 December 2016 DB_HOTBACKUP(1)
Generated by $Id: phpMan.php,v 4.55 2007/09/05 04:42:51 chedong Exp $ Author: Che Dong
On Apache
Under GNU General Public License
2024-04-27 06:36 @3.140.198.173 CrawledBy Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; ClaudeBot/1.0; +claudebot@anthropic.com)