NAME
db4.6_hotbackup - Create "hot backup" or "hot failover" snapshots
SYNOPSIS
db4.6_hotbackup [-cDuVv] [-d data_dir ...] [-h home] [-l log_dir] [-P
password] -b backup_dir
DESCRIPTION
The db4.6_hotbackup utility creates "hot backup" or "hot failover"
snapshots of Berkeley DB database environments.
The db4.6_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 db4.6_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 db4.6_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, db4.6_hotbackup should always be given the
chance to detach from the environment and exit gracefully. To cause
db4.6_hotbackup to release all environment resources and exit cleanly,
send it an interrupt signal (SIGINT).
The db4.6_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).
28 January 2005