Tag Archives: Logshipping

Database Mirroring Vs Log Shipping

Please read the below table to find out the diffrence between mirroring and log shipping.

Database Mirroring Log-shipping
Database mirroring is functionality in the SQL Server engine that reads from the transaction log and copies transactions from the principal server instance to the mirror server instance.  Database mirroring can operate synchronously or asynchronously. Log shipping is based on SQL Server Agent jobs that periodically take log backups of the primary database, copy the backup files to one or more secondary server instances, and restore the backups into the secondary database(s).  Log shipping supports an unlimited number of secondary’s for each primary database.
Database mirroring can operate synchronously or asynchronously. If configured to operate synchronously, the transaction on the principal will not be committed until it is hardened to disk on the mirror. Log shipping is always asynchrony. Log shipping totally depends on the log backup and restore schedule
Database mirroring supports only one mirror for each principal database. That means DB mirroring is at database level Log-shipping can work on database and server level. You can configure multiple databases in logshipping
Data Transfer:    Individual T-Log records are transferred using TCP endpoints
Transactional Consistency:  Only committed transactions are transferred
Server Limitation:   Can be applied to only one mirror server
Failover:   Automatic
Failover Duration:  Failover is fast, sometimes < 3 seconds but not more than 10 seconds
Role Change:   Role change is fully automatic
Client Re-direction:  Fully automatic as it uses .NET 2.0/.Net 3.0
With Log Shipping:

Data Transfer:    T-Logs are backed up and transferred to secondary server

Transactional Consistency:  All committed and un-committed are transferred

Server Limitation:   Can be applied to multiple stand-by servers

Failover:   Manual

Failover Duration:  Can take more than 30 mins

Role Change:   Role change is manual

Client Re-direction:  Manual changes required

Support only full recovery model Supports full and bulk-logged recovery model
Mirror database is always in recovery mode. To read it you have use database snapshot. You can use the stand-by option to read the database on standby server
Auto Page Recovery introduced with SQL SERVER 2008 so it will recover the damaged pages. Not supported