SAS Scalable Performance Data Server 4.5, Руководство администратора

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Back Up and Restore SPD Server Table Indexes
using System Full Backups
Back Up and Restore SPD Server Table Indexes Using System Full
Backups
Restoring indexes from system full backups and restores is not as clean as restoring indexes
from SPD Server full backups and restores. To understand why, consider the two available
methods for restoring indexes from a system full backup:
• restore the index dynamically as the table is restored
• recreate the index after the table is restored.
What decides which method to use? You must balance the time and resources needed to
back up the index against the time needed to re-create the index when the table is restored.
Method 1 – Restore the Index Dynamically
To restore the index dynamically, you must include the table index files in the full backup
and restore of the table. To determine which index files to include, use
spdsls
with the
-i
index option. The output lists component files for each table in the domain that is
intended for full backup.
When restoring a table, you must first restore the table metadata, data, and index files from
the last full backup archive. Then use
spdsrstr
to perform incremental restores. As the
tables are restored, the indexes are dynamically updated to include any new or modified
records.
In summary, the first method trades the additional resources required for full backup of the
table index files, which can be very large, against the potentially short time that might be
required to restore them. You can restore indexes for a table that has not had any incremental
changes after the system full backup by using a system full restore.
Method 2 – Recreate the Index after the Table Is Restored
If you use this method, you do not need to include the index files in the table's full backup.
Thus, when running spdsls to list the component files for each table in the domain that you
intend to back up, leave off the -i index option. The spdsls utility then outputs a list that
excludes index files.
A cautionary note about method 2: If you do not save index information, you can experience
problems when you attempt to fully restore the table. The reason: the table's metadata will
have information about the index files which can be missing or out of date. As a result, the
metadata no longer mirrors the table.
Before you can perform an incremental restore of the table, you must first repair the table
metadata. To repair the metadata, use PROC DATASETS to modify the table and delete
all of the indexes, then run spdsrstr to restore the table. After performing the incremental
restores of the table, use PROC DATASETS again to modify the table and create the
indexes.
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Chapter 19 • SPD Server Backup and Restore Utilities