--- title: taosdump description: "taosdump is a tool application that supports backing up data from a running TDengine cluster and restoring the backed up data to the same or another running TDengine cluster." --- ## Introduction taosdump is a tool application that supports backing up data from a running TDengine cluster and restoring the backed up data to the same or another running TDengine cluster. taosdump can back up a database, a super table, or a normal table as a logical data unit or backup data records in the database, super tables, and normal tables. When using taosdump, you can specify the directory path for data backup. If you do not specify a directory, taosdump will back up the data to the current directory by default. Suppose the specified location already has data files. In that case, taosdump will prompt the user and exit immediately to avoid data overwriting which means that the same path can only be used for one backup. Please be careful if you see a prompt for this. taosdump is a logical backup tool and should not be used to back up any raw data, environment settings, Users should not use taosdump to back up raw data, environment settings, hardware information, server configuration, or cluster topology. taosdump uses [Apache AVRO](https://avro.apache.org/) as the data file format to store backup data. ## Installation There are two ways to install taosdump: - Install the taosTools official installer. Please find taosTools from [All download links](https://www.taosdata.com/all-downloads) page and download and install it. - Compile taos-tools separately and install it. Please refer to the [taos-tools](https://github.com/taosdata/taos-tools) repository for details. ## Common usage scenarios ### taosdump backup data 1. backing up all databases: specify `-A` or `-all-databases` parameter. 2. backup multiple specified databases: use `-D db1,db2,... ` parameters; 3. 3. back up some super or normal tables in the specified database: use `-dbname stbname1 stbname2 tbname1 tbname2 ... ` parameters. Note that the first parameter of this input sequence is the database name, and only one database is supported. The second and subsequent parameters are the names of super or normal tables in that database, separated by spaces. 4. back up the system log database: TDengine clusters usually contain a system database named `log`. The data in this database is the data that TDengine runs itself, and the taosdump will not back up the log database by default. If users need to back up the log database, users can use the `-a` or `-allow-sys` command-line parameter. 5. Loose mode backup: taosdump version 1.4.1 onwards provides `-n` and `-L` parameters for backing up data without using escape characters and "loose" mode, which can reduce the number of backups if table names, column names, tag names do not use This can reduce the backup data time and backup data footprint if table names, column names, and tag names do not use `escape character`. If you are unsure about using `-n` and `-L` conditions, please use the default parameters for "strict" mode backup. See the [official documentation](/taos-sql/escape) for a description of escaped characters. :::tip - taosdump versions after 1.4.1 provide the `-I` argument for parsing Avro file schema and data. If users specify `-s` then only taosdump will parse schema. - Backups after taosdump 1.4.2 use the batch count specified by the `-B` parameter. The default value is 16384. If, in some environments, low network speed or disk performance causes "Error actual dump ... batch ..." can be tried by challenging the `-B` parameter to a smaller value. ::: ### taosdump recover data Restore the data file in the specified path: use the `-i` parameter plus the path to the data file. You should not use the same directory to backup different data sets, and you should not backup the same data set multiple times in the same path. Otherwise, the backup data will cause overwriting or multiple backups. :::tip taosdump internally uses TDengine stmt binding API for writing recovery data and currently uses 16384 as one write batch for better data recovery performance. If there are more columns in the backup data, it may cause a "WAL size exceeds limit" error. You can try to adjust to a smaller value by using the `-B` parameter. ::: ## Detailed command-line parameter list The following is a detailed list of taosdump command-line arguments. ``` Usage: taosdump [OPTION...] dbname [tbname ...] or: taosdump [OPTION...] --databases db1,db2,... or: taosdump [OPTION...] --all-databases or: taosdump [OPTION...] -i inpath or: taosdump [OPTION...] -o outpath -h, --host=HOST Server host dumping data from. Default is localhost. -p, --password User password to connect to server. Default is taosdata. -P, --port=PORT Port to connect -u, --user=USER User name used to connect to server. Default is root. -c, --config-dir=CONFIG_DIR Configure directory. Default is /etc/taos -i, --inpath=INPATH Input file path. -o, --outpath=OUTPATH Output file path. -r, --resultFile=RESULTFILE DumpOut/In Result file path and name. -a, --allow-sys Allow to dump system database -A, --all-databases Dump all databases. -D, --databases=DATABASES Dump inputted databases. Use comma to separate databases' name. -N, --without-property Dump database without its properties. -s, --schemaonly Only dump tables' schema. -y, --answer-yes Input yes for prompt. It will skip data file checking! -d, --avro-codec=snappy Choose an avro codec among null, deflate, snappy, and lzma. -S, --start-time=START_TIME Start time to dump. Either epoch or ISO8601/RFC3339 format is acceptable. ISO8601 format example: 2017-10-01T00:00:00.000+0800 or 2017-10-0100:00:00:000+0800 or '2017-10-01 00:00:00.000+0800' -E, --end-time=END_TIME End time to dump. Either epoch or ISO8601/RFC3339 format is acceptable. ISO8601 format example: 2017-10-01T00:00:00.000+0800 or 2017-10-0100:00:00.000+0800 or '2017-10-01 00:00:00.000+0800' -B, --data-batch=DATA_BATCH Number of data per query/insert statement when backup/restore. Default value is 16384. If you see 'error actual dump .. batch ..' when backup or if you see 'WAL size exceeds limit' error when restore, please adjust the value to a smaller one and try. The workable value is related to the length of the row and type of table schema. -I, --inspect inspect avro file content and print on screen -L, --loose-mode Using loose mode if the table name and column name use letter and number only. Default is NOT. -n, --no-escape No escape char '`'. Default is using it. -T, --thread-num=THREAD_NUM Number of thread for dump in file. Default is 5. -g, --debug Print debug info. -?, --help Give this help list --usage Give a short usage message -V, --version Print program version Mandatory or optional arguments to long options are also mandatory or optional for any corresponding short options. Report bugs to . ```