Home/ Questions/Q 844721
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-05-15T06:19:54+00:00

I am currently crossing the jungle of SQL Server scale-out technologies like replication, log-shipping,

  • 0

I am currently crossing the jungle of SQL Server scale-out technologies like replication, log-shipping, mirroring… I have the following constraints on my choice:

  • I want the read-only load to be spread accross the primary and the secondary (mirror, subscriber) server
    • Write load can be sent directly to the primary server
    • The solution should be nearly maintainance free. Schema changes should just replicate to the secondary server (attention: replication has some serious constraints here as it seems)
    • Written data should be accessible very quickly (in under 1s, but better would be instantaneously) on the secondary server
    • On server failure I can tollerate up to one hour of data loss easily. I am more concerned with easy scalability

Here are some options for what I could pick: http://msdn.microsoft.com/en-us/library/bb510414.aspx. Any experience you could share?

Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. Editorial Team

    Those are all High Availability solutions, not scale-out. SQL Server has no easy scale-out solution, nor do any other (relational) databases. Using master-slaves replication scales as much as allowed by the master write scale-up possibility. Using master-master replication multiplexes the writes and comes with consistency issues. Almost all large-scale deployments that had attempted replication based solutions had to abandon it.

    One alternative is to rethink your application in terms of independent data-fiefdoms communicating by messaging, the way MySpace scales out.

    Another alternative is to abandon some constraints (write consistency, read consistency, recoverability, typed schemas, referential integrity) and choose a nosql engine that can scale out freely once liberated of these constraints (Cassandra, HBase, MongoDB).

    Ultimately scale-out is such a fundamental requirement that you must design your application around the solution and embrace all the (severe) restrictions imposed by scale out. Note though that all relational engines can scale -up a long way and the worldwide number of deployments that require scale out beyond what a a database can scale-up can be counted on your fingers.

    • 0