replication

No ZFS Support for EMC Replication Manager

As I originally blogged, I was hoping to use EMC snapshots to perform server-less/network-less backups. EMC provides two main tools for managing snapshots in this type of situation:

  • EMC Replication Manager
  • EMC PowerSnap Networker Module

The PowerSnap Module supposedly automates taking snapshots for the purpose of backups, while Replication Manager supposedly provides a much more robust package.

With Replication Manager you might create a policy to take a snapshot every five minutes, keep the last 10, and use those for backups whenever necessary.

To make a long story short, Replication Manager is useless for LUNs with ZFS. According to EMC, this won't change in the near future. PowerSnap also has no support for taking snapshots of LUNs with ZFS on them so basically EMC has no server-less backup offerings for Solaris with ZFS.

EMC Replication Manager in Solaris

UPDATE: No ZFS Support for Replication Manager in the near future

Using storage level snapshots can be used to run backups without directly requiring resources from the original host.

EMC Replication Manager coordinates the creation of application consistent snapshots across all the hosts in your network. It handles scheduling creation/expiration of snapshots,  mounting and unmounting from backup servers, etc. from a single console.

Although it is not tightly integrated into EMC Networker like the similar Networker PowerSnap module, it can be used to start a backup process after taking a new snapshot and it has the capability to manage snapshots unrelated to backups from a GUI.

While the data sheet claims support for Solaris, there are several caveats which I have run into.

Real Time Reporting Databases

Reporting projects are the kind of projects which never seem to end. After a couple iterations I've come to the following conclusions:

  1. Absolutely no reports should run on a production database.
  2. Moving/aggregating data from a production database to a reporting database using ETL tools prone to synchronization issues and pretty unreliable.
  3. The best option is to set up real time replication of the data and build additional views on that.

Unfortunately, if you need to get data from heterogeneous databases, ie. Oracle, MySQL, SQL Server, etc. into a single reporting database, replication is not a simple solution. If you are running expensive database software in production, it may not be cost effective to run the same database for reporting.

Of course there are cross database replication solutions like Golden Gate or SharePlex but they are very expensive. I had already given up on getting data from Oracle into MySQL for reports when I stumbled across Tungsten Replicator.