- How It Works
- Advantages of Log Shipping
- Disadvantages of Log Shipping
- Log Shipping Setup
- Failover
- Summary
Disadvantages of Log Shipping
Unfortunately, log shipping does have a few issues that the DBA should be aware of prior to relying on this method of failover:
Possible data loss when the primary server fails. If the primary server becomes completely unusable, transactions that occurred after the last transaction log backup that was copied to the standby server are lost. For example, suppose that server A fails at 5 a.m. and you cannot get to it at all. If the last backup copied to server B was taken at 4:45 a.m., all transactions that occurred between 4:45 a.m. and 5 a.m. are lost forever.
Some manual DBA work is required to bring the standby server online, as discussed in this article.
Log shipping setup cannot be scripted. This means that you cannot mimic the production environment for testing purposes without going through the wizard screens.
The Enterprise edition of SQL Server 2000 is required on primary and standby servers. If you run any other version/edition of SQL Server, you're out of luck. The Developer edition can be used to learn how to set up log shipping, but it cannot be used in a production environment. Note however, that log shipping is merely an automated way of copying transaction log backups, so a savvy DBA can easily set up jobs to accomplish the same functionality.
Difficult troubleshooting. Log shipping usually works very well, but if there are problems, they're difficult to troubleshootdocumentation is sparse and typically not helpful for solving a particular problem. Fortunately Microsoft's Knowledge Base articles have good information for troubleshooting log-shipping issues.
Each database that needs to be log-shipped must be set up through a separate maintenance plan.