Mixed Storage Types  

Result: Data loss  

The signature

Mixed Storage Types

The impact

In the event that a disaster replica is needed for DR purposes, these disaster recovery replica will be unusable and resulting in data loss. The production database or file system replication is incomplete or inconsistent and will not be recoverable from the replication technology. Data will need to be recovered at the disaster recovery site and restored from a recent backup increasing the time to recovery.

Technical details

In this example, the production database is across three storage volumes. The intent is to replicate these production storage volumes to the disaster recovery site, however, one production storage volume is not of the same storage type and is actual a local disk and therefore not being replicated. The result is a incomplete replica at the disaster recovery site.

Can it happen to me?

This is a common gap found in highly evolving environments with many teams involved in the provisioning process. The handoffs in the provisioning process involving the storage team, platform team and the database teams are complex and many times mixed storage (including local, EMC, NetApp etc.) devices are used to create volume groups (Veritas or other LVM software) in which databases are created or extended on.