When is Tape Not Enough?
Replication or Backup ?
• Replicated images are “ready to go”
– May only need a short recovery or rollback based on:
• Journaling file systems or databases
• Crash checkpoints
– Can execute the replication technique closer to
• More frequent replications
• Backup data has multiple recovery points
– May require considerable time to recover if:
• Searching through a series of tapes
• Decompressing data
• Restoring a corrupt catalog before recovery
• Performing a Crash Recovery
– recovering from a specialized “Crash File”
– implemented differently by different software vendors
Replicated images are ready to go whereas backup has multiple recovery
points. We need to look at the 2 different architectures.
When we look at data replication techniques, we’re talking about disk based
replication. So its either going to be
In-system replication – snapshots and split mirrors
Between sub-systems – remote mirroring