NAME
dbhotbackup - Create "hot backup" or "hot failover" snapshots SYNOPSIS
dbhotbackup [-cDEguVv] [-d datadir ...] [-h home] [-l logdir] [-P
password] -b backupdir DESCRIPTION The dbhotbackup utility creates "hot backup" or "hot failover" snap‐ shots of Berkeley DB database environments. The dbhotbackup utility performs the following steps: 1. Sets the DBHOTBACKUPINPROGRESS 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 DBHOTBACKUPINPROGRESS flag in the environment. The dbhotbackup utility does not resolve pending transactions that are
in the prepared state. Applications that use DBTXN->prepare should specify DBRECOVERFATAL when opening the environment, and run
DBENV->txnrecover to resolve any pending transactions, when failing over to the hot backup. OPTIONS
-b backupdir 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 dbhotbackup MUST be run by the same user that owns the database. If dbhot‐ 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 DBCONFIG 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 DBCONFIG 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 DBCONFIG file, instead of from the default locations. 4. The DBCONFIG 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 DBCONFIG 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 datadir 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 logdir 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 DBCONFIG 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 DBCONFIG file specifies one or more absolute pathnames,
files in those source directories will be copied to the top- level target directory. Third, the DBCONFIG 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 DBCONFIG configuration file copied into the target directory would then point at the source directories and running recovery would corrupt the source data files. The dbhotbackup utility uses a Berkeley DB environment (as described
for the -h option, the environment variable DBHOME, 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, dbhotbackup should always be given the chance to detach from the environment and exit gracefully. To cause dbhotbackup to release all environment resources and exit cleanly, send it an interrupt signal (SIGINT). EXIT STATUS The dbhotbackup utility exits 0 on success, and >0 if an error occurs. ENVIRONMENT DBHOME
If the -h option is not specified and the environment variable DBHOME is set, it is used as the path of the database home, as
described in DBENV->open. SEE ALSO dbarchive(1) dbcheckpoint(1) dbdeadlock(1) dbdump(1) dblogver‐ ify(1) dbload(1) dbprintlog(1) dbrecover(1) dbreplicate(1) dbstat(1) dbtuner(1) dbupgrade(1) dbverify(1) BerkeleyDB 5.3.21 06 December 2016 DBHOTBACKUP(1)