A cyclic redundancy check has been added for accidental changes to raw
data for database or transaction dumps created with compression. Use the cyclic redundancy
check for checking and verifying that the compression blocks can be correctly read and
decompressed.
The syntax
is:
dump database database_name to dump_device with compression=n,verify={crc | read_after_write}
load database database_name from dump_device with verify[only]=crc
Where:
- verify=crc – indicates that you are performing a cyclic
redundancy check.
- verify=read_after_write –
Backup Server rereads every compressed block after writing and decompresses it.
If Backup Server finds an error, it prints the offset in the file in which it
finds the error. verify=read_after_write is
only applicable with the dump database
command.
This example verifies database
new_dump before dumping it to the
mydumpdev
device:
dump database new_dump to mydumpdev with compression=x,verify=read_after_write
This example performs a cyclic redundancy check as it loads the
new_dump
database
dump:
load database new_dump from mydumpdev with verify[only]=crc
This example performs a cyclic redundancy check and rereads every
compressed block before dumping database
new_dump to
the
mydumpdev
device:
dump database new_dump to mydumpdev with compression=x,verify=read_after_write,verify=crc
Usage:
- Dumps created without the verify=crc parameter use the same format as earlier versions of
Backup Server.
- The verify=crc option is
ignored if the database was not originally dumped using verify=crc.
- You cannot load dumps that include cyclic redundancy checks with versions of
Backup Server that do not include this functionality.
- verify={crc | read_after_write} checks are applicable only
for files created using the with compression parameter.
- verify=crc works with any file type, including raw devices,
disk files, tapes, pipes, or APIs. However,
verify=read_after_write requires a ‘seek back’ for
rereading the block, and is applicable only with raw devices and disk files.
- If you include verify={crc |
read_after_write} parameters that are not applicable, they are
ignored and no error message is raised.