Backup Server dump files and compressed dumps

When you perform dump database or dump transaction using an archive file that already exists, Backup Server automatically checks the header of the existing dump archive. If the header is unreadable, Backup Server assumes that the file is a valid non-archive file, and prompts you to change the dump archive with the following message:

Backup Server: 6.52.1.1: OPERATOR: Volume to be overwritten on '/opt/SYBASE/DUMPS/model.dmp' has unrecognized label data.
Backup Server: 6.78.1.1: EXECUTE sp_volchanged
	@session_id = 5,
	@devname = '/opt/SYBASE/DUMPS/model.dmp',
	@action = { 'PROCEED' | 'RETRY' | 
'ABORT' },
	@vname = <new_volume_name>

For this reason, if you perform dump database or dump transaction to a file without the compress:: option into an existing compressed dump archive, Backup Server does not recognize the header information of the archive because it is compressed.

Example

The second dump database reports an error, and prompts you with sp_volchanged:

dump database model to 'compress::model.cmp'
go
dump database model to 'model.cmp'
go

To prevent this error, either:

Include the with init option in your subsequent dump database and dump transaction commands:

dump database model to 'compress::model.cmp'
go
dump database model to 'model.cmp'
   with init
go

Include the compress:: option in subsequent dump database and dump transaction commands:

dump database model to 'compress::model.cmp'
go
dump database model to 'compress::model.cmp'
go

Using the compress:: option into uncompressed dump archives, as in this example, does not generate errors:

dump database model to 'model.cmp'
go
dump database model to 'compress::model.cmp'
go