Pros and Cons of Each Backup Approach

SPD Server Utilities

Benefits

  • Incremental backups copy only changed rows, instead of the entire table, which conserves disk space.
  • Incremental restores replace specific rows, rather than an entire table, which can save time.
  • The utilities will not back up tables that are being updated.

Limitations

The SPD Server backup utility does not back up the following:
  • cluster tables. In order to back up a cluster table, you must undo the cluster, back up the individual member tables, and then remake the cluster. Likewise, to restore a damaged cluster table, you must undo the cluster, restore the member tables individually, and remake the cluster.
  • table WHERE constraints.
  • index files. The backup utility backs up only the definition of the index from the metadata. The index is re-created by using the metadata when a full restore is performed.
Incremental backups can take a long time. The utilities use SQL to push queries to the tables being backed up and restored. To accommodate this, three extra columns are added to each table—Last Date Modified, Deleted, and Modified—which are hidden to the user. Backup queries for full backups read the entire table. Backup queries for increments must push a query to set the rows modified since the last backup using the values in the Last Date Modified column. The Last Date Modified column is not indexed. This can be a very long query for a large table.

System Backup Utilities

Benefits

  • System utilities do not parse the data set. Therefore, this type of backup usually runs faster than the SPD Server utility when you are doing a full backup.
  • System utilities back up table indexes.

Limitations

  • System utilities do not coordinate with tables being modified. They just read the table parts and back them up, so keeping them in sync could be an issue.
Last updated: February 3, 2017