Networker Deduplication Guidelines - HP StorageWorks 12000 - Virtual Library System EVA Gateway Manual

continuation, No space left on device, at file 2 record 0
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Media is marked as full and the application selects another tape and progresses through the
same until all tapes are listed as "full." The recommended action is to obtain and install HPUX
11.31 patch PHKL_36312.

Networker Deduplication Guidelines

In addition to the NetWorker general guidelines, the following guidelines apply to a VLS with
deduplication enabled:
• Pools: Use as few pools as possible to quickly fill up tapes. You should create a separate pool for
each projected retention period. For example:
• Daily (except for the last day of the month)
• One Month
• One Year
• Enable auto-ejection: Enable auto-ejection by setting the idle device timeout parameter in
the NetWorker autochanger (tapes will not be deduplicated until they are ejected from the virtual
tape drive).
• Disable multiplexing in Oracle RMAN backups: In the VLS firmware version 3.3.0 (or higher) the
scripting requirements for Oracle data files have been relaxed, so it is no longer mandatory to
assign prefix naming conventions to Oracle data files to make sure the data is properly deduplic-
ated. The minimum requirement for RMAN to deduplicate efficiently is to disable multiplexing
(where you have multiple RMAN streams concurrently writing to the same drive). You can disable
multiplexing by setting FILESPERSET=1 for each database backup in the RMAN scripts (not
needed for archive logs or control files). You can define additional channels to increase the number
of parallel backup processes running with FILESPERSET=1 to generate the same RMAN perform-
ance as before, so that each stream goes to a different virtual tape drive.
The following RMAN settings will not deduplicate because they always generate totally unique
data every backup:
• Incremental backups
• RMAN compressed backups
• RMAN encryption
NOTE:
If you had previously configured the prefix naming conventions in your Oracle RMAN scripts, this
will continue to deduplicate efficiently with the firmware version 3.3.0 (or higher), but you should
ensure that multiplexing is disabled as well. If you wish to remove the prefix naming conventions,
you will need to rename the backup job name in NetBackup. (New backup jobs will not deduplicate
against the previous jobs with the different job name.)
• Disable multiple streams per data file for SQL database backups: Multiple streams from a given
data file will reduce deduplication effectiveness. For some database backups, NetWorker can
create multiple savestreams per database file. Disabling this feature is critical when using dedu-
plication. Multiple savesets from a database is not an issue, only multiple streams from a data file.
Disable the "Striped Backup" feature in the NetWorker Module for Microsoft SQL Server because
this creates multiple streams from each data file. To disable this for a scheduled backup, edit the
NetWorker client object for the SQL backup and remove the -Sn option from the backup command
(n is the number of parallel streams per data file; removing this argument from the backup com-
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