NAME¶
db4.7_hotbackup - Create "hot backup" or "hot failover"
snapshots
SYNOPSIS¶
db4.7_hotbackup [-cDuVv] [-d data_dir ...] [-h home] [-l log_dir] [-P
password] -b backup_dir
DESCRIPTION¶
The db4.7_hotbackup utility creates "hot backup" or "hot
failover" snapshots of Berkeley DB database environments.
The db4.7_hotbackup utility performs the following steps:
- 1.
- If the -c option is specified, checkpoint the source home
database environment, and remove any unnecessary log files.
- 2.
- 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.
- 3.
- 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.
- 4.
- 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.
- 5.
- Perform catastrophic recovery on the hot backup.
- 6.
- Remove any unnecessary log files from the hot backup.
The db4.7_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
- 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.
- -d
- 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.
- -h
- Specify the source directory for the backup, that is, the
database environment home directory.
- -l
- Specify a source directory that contains log files; if none
is specified, the database environment home directory will be searched for
log files.
- -P
- 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 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 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 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 db4.7_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 environment,
db4.7_hotbackup should always be given the chance to detach from the
environment and exit gracefully. To cause db4.7_hotbackup to release all
environment resources and exit cleanly, send it an interrupt signal (SIGINT).
The db4.7_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.
AUTHORS¶
Oracle Corporation. This manual page was created based on the HTML documentation
for db_hotbackup from Sleepycat, by Thijs Kinkhorst
<thijs@kinkhorst.com>, for the Debian system (but may be used by
others).
