Kbase P118156: Is Progress compliant with Double-Take Replication Software
| Autor |
Progress Software Corporation - Progress |
| Acesso |
Público |
| Publicação |
25/08/2010 |
|
Status: Verified
GOAL:
Is Progress compliant with Double-Take Replication Software
GOAL:
Are 3rd Party Replication Software certified for Progress ?
FACT(s) (Environment):
All Supported Operating Systems
Progress/OpenEdge Versions
FIX:
No. This product has never been certified against our technology, nor do we have any plans to do so. We don't support any 3rd party software replication solutions. The only supported solution is OpenEdge Replication.
Some (but not exclusive) technical aspects to consider would include:
1. Double Take, is a software replication product that transfers data, at the byte level, from one disk to a secondary disk, offering replication and failover for all types of applications and databases. On-going changes are transmitted continuously. A target disk receives and applies the changes to target volumes. In order to guarantee recovery, a Progress database needs to have the write ahead logging prototcol observed. The Progress Before Image (bi) and After Image (ai) files must be written before the database files. The only way to maintain and ensure the integrity of Progress data would be to update the blocks in the same order that Progress updates them, but Double Take cannot differentiate between these Progress files. In a true 'disaster recovery' scenario, data can be easily be lost as a result of the 'system down' situation, thus causing database integrity and even accessibility issues afterwards. For example: when the source system dies, it's most likely that the physical database files are out of sync with the BI files, which means that BI rollback recovery may not even be possible on the target database using a Double-Take backup.
2. When the database is running shared-memory, data are in three different locations: memory, binary recover logs and the embedded storage. So any backup that is restored needs to ensure that these three states are recorded at exactly the same time-splice to ensure integrity. OpenEdge Replication uses on continual trans