Storix Software SBAdmin User Guide - Manual (Page 159)

Read Error Settings
This section provides information on the options for controlling the way read errors are handled when reading
from the backup media. Although the Backup Administrator itself provides a reliable backup, the media on which
the backup is placed can sometimes become corrupt. These options will allow you to select how much work the
application should try to recover from errors reading from a corrupt tape. To change these settings, select
Utilities !Backup/Restore Settings!Read Error Settings from the menu bar. The following screen will appear:
The following is an explanation of each field:
1. Maximum of data read errors before read failing: When a read error is encountered, the media
device driver, it will, by default, attempt to retry the read up to the number of times specified in the field
"Maximum number of retries on each read error" below. If the application is unable to read the data,
a read error is produced, and the process will either skip the missing data entirely or pad the missing
data with NULL bytes, as defined by the field "Pad missing data blocks with nulls?".
This option allows you to specify the maximum number of read errors that are produced before the
backup aborts. You may specify any number up to 32768 in this field, or you may use a zero (0) to
indicate that the reading should abort after the first read error.
2. Maximum number of data sync errors before read failing: An individual read of the backup is
performed for each buffer, defined by the buffer size of the backup. At the beginning of each buffer is a
special key that is used to ensure that the data is being read at the correct point. A " data sync " error
occurs when the key is not encountered when reading the data or the key has an incorrect sequence
number.
When a sync error occurs, the process will either skip the missing data altogether or pad the missing
data with NULL bytes, as defined by the field "Pad missing data blocks with nulls?".
This field determines the maximum number of sync errors that may occur before the reading aborts.
The value of this field may be any number up to 32768. Using a value of zero (0) indicates that the
reading should abort after the first sync error.
3. Maximum number of retries on each read error: When a read error occurs, the process will, by
default, attempt to re-read the same buffer of data up to the number of times specified by this field. The
reading will abort when a read error occurs and has been retried the number of times indicated. You
may enter a number up to 32768. An entry of zero (0) indicates that no retries should be attempted.
Most tape devices, including 8MM tape drives, will return an error very quickly when
a read error occurs, and will allow retries to be attempted from the same data
location. Others, such as DDS 4MM tape drives, take up to 2 minutes to return from a
read error. These tape devices also do not allow read retries, but will still take 2
minutes to return from an attempt. Therefore, for these, and similar devices, you will
want to set this value to zero (0) since retries are not supported, and any attempts
will appear to pause the reading indefinitely.
Storix System Backup Administrator 159 Version 8.2 User Guide