how can i backup multi database use milvus-backup

[hxlsky]

how can i backup multi database use milvus-backup?
-d, --databases string databases to backup
the -d just only set a database name?

[yhmo]

./milvus-backup create --help

Usage:
  milvus-backup create [flags]

Flags:
  -n, --name string                   backup name, if unset will generate a name automatically
  -c, --colls string                  collectionNames to backup, use ',' to connect multiple collections
  -d, --databases string              databases to backup
  -a, --database_collections string   databases and collections to backup, json format: {"db1":["c1", "c2"],"db2":[]}
  -f, --force                         force backup, will skip flush, should make sure data has been stored into disk when using it
      --meta_only                     only backup collection meta instead of data
      --rbac                          whether backup RBAC meta
  -h, --help                          help for create

The "--databases" is the database to backup, which means if you didn't set "--colls", this command will backup all the collections inside the database.

The "--database_collections" is what you want, it is a JSON format string to specify the target collection and which database it belongs.
Assume you want to backup collection "AAA" in the database "my_db", you can set --database_collections {"my_db": ["AAA"]}

From the source code of milvus-backup, the major logic is:

• If "--databases" is specified, the database names are converted to the JSON string of "database_collections" string and assigned to "--database_collections":
  https://github.com/zilliztech/milvus-backup/blob/e22a744412782a8d0f04a89f5a8c27b5d37abc7c/cmd/create.go#L54

• If "--database_collections" is specified, all collections of the databases will be backuped:
  https://github.com/zilliztech/milvus-backup/blob/e22a744412782a8d0f04a89f5a8c27b5d37abc7c/core/backup_impl_create_backup.go#L136

• If "-databases" and "--database_collections" are not specified, it gets the collection names from "--colls", and backup the collections from the "default" database

So, if you want to backup collections from different databases, just use the "--database_collections" like {"db1":["c1", "c2"],"db2":[]}

[hxlsky]

i want to backup 2 database,db01 and db02,how can i do?

[yhmo]

--database_collections {"db01": [], "db02": []}

or

--databases db01,db02