HP BB118BV - StorageWorks Data Protector Express Package, User Manual, Page: 129 / 365

Chapter 8: Job Options 111
with any other media except with the expected media. Additionally, this option will not search for another
device that might contain the proper media.
Write mode
The Write mode is either Append to all media , Append to first media, overwrite others or Overwrite
all media . For automatic rotation jobs, Data Protector Express overwrites all media. For other jobs, Data
Protector Express uses the write mode settings set by the user. For more information, see Backup options
automatically updated
on page 113.
This mode determines whether the old data on the media is overwritten with new data or whether the new
data is
appended
to the end of the old data. When media is overwritten, all of the data previously stored
on it is lost. Appending data will preserve the old data.
Unless the media is meant to be stored permanently, select Overwrite all media . This is because when
media are rotated (reused), Data Protector Express overwrites it. If you have appended data to the media,
overwriting will result in the loss of not just the oldest material, but all of the data on the media, including
the most recent. For this reason, use
Overwrite all media for media you wish to reuse through rotation,
such as media that are part of a set of daily incremental backups, and Append to all media or Append to
first media, overwrite others
for media meant for permanent storage.
Appending is useful if the number of media is limited or if the media are several times larger than the size
of the job. For example, a one gigabyte media could hold the contents of four jobs that are less than 250
Mbytes if these jobs were appended. However, if overwrite mode is selected, only one job will be stored
on media at once. Similar comments apply to other types of media.
Append to all media: This setting instructs Data Protector Express to append all data to the end of the
media. No data is overwritten. Select this setting for permanent storage.
Append to first media, overwrite others: This setting instructs Data Protector Express to append data to the
end of the first media, but to overwrite all media that follows. For example, Data Protector Express will
not overwrite the first media inserted, but will overwrite the second, third and later media. This setting is
useful if you have a set of media with old data you no longer need. By selecting this option, Data
Protector Express preserves your most recent data on the first media, but overwrites older, unneeded
media.
Overwrite all media: This setting instructs Data Protector Express to overwrite all media. All data on media
that is overwritten is lost. Use this option for media that are going to be recycled.
Auto Verify Mode
The Auto verify mode is either
No verify
,
Full verify
or
Quick verify
.
After Data Protector Express backs up a file onto a piece of media, it can verify that the file was backed
up correctly. Data Protector Express reads the file from the media and compares it to the original file
(
Full verify
mode). If any discrepancies between the two files are found, the file is considered to have
failed the backup.
It is strongly recommended that the
Auto verify mode
be set to
Full verify
. Verifying that data has been
correctly written to the media is an essential part of a comprehensive backup program. Also, verifying the
files ensures that the media and the media drive are working correctly. Restoring data after a disaster is no
time to discover that the data was incorrectly stored to begin with.
No verify: This setting instructs Data Protector Express to skip the verification step. It is not
recommended.