Can a Sybase/Solaris master combined with a farm of Sybase/Linux read-only replicas be made a serious production-worthy environment?
Our current environment has a Sybase/Solaris master and Solaris warm backup. We use the warm backup to handle all our read-only activity, which is 90% of the traffic. When replication fails, we can switch reads to the master while a dump and load to the backup is completed. No downtime.
With a Linux cluster of replicas, a replication server failure would not appear to allow us to dump and load to the replicas while the master continues to accept writes. Is this a workable scenario? Would another model work?
Before deploying Linux you have to appreciate that at this moment in time there is no heterogeneous dump and load facility from Solaris to Linux. This facility (i.e. the ability to dump a Sybase database on Solaris and load it into Linux) is expected to be available in Q1 2005.
So if you have you production running on Sybase/Solaris, you need to reverse engineer your database and populate it with the current production data. More often than not this will be a weekend work. You can obviously set this one up by selecting tables in stages and use Sybase replication server to keep databases in sync thereafter. If your replicate database on Linux gets out of sync with the production on Solaris, you have a number of options.
- If the failure has affected a limited number of tables, you can easily BCP out data from the production and BCP in data to the replicate database on Linux.
- You can use the Sybase utility autocorrect for each table to replace an update with a delete followed with an insert. This will only work if you have not used "reoplicate minimal columns" in your replication definitions.
- If a large number of tables affected you may have to go through the process of BCPing out all tables and BCPing them again. This is not ideal.
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This was first published in July 2004