Data Replication Related Questions

[Sanjay Kumar Suri]

We have been using storage (XP512 to XP1024) based replication method (CA) to transfer Oracle log files (10g) from primary to DR site. On an average we transfer 50 GB data on daily basis. The application used is SAP 6.0 which runs on HP-UX 11.23. The DR site is more than 1000 km away and CNT boxes are deployed at both sites.

We are looking for alternative to above solution making using riverbed kind of acceleration boxes to conserve the bandwidth in the ration of 1:3.5 (with CNT: with riverbed). We have thought of following alternatives:
1. Oracle Data Guard
2. ftp based server-to server transfer

Questions:

1. What are pro-n-cons of above approaches v/s storage based replication?
2. What are the different utilities/tools/command (like ftp) to transfer log files (for server-to-server) transfer with in-built intelligence (like retransfer after network link failure & reporting)?
3. How to manage multiple ODG implementations for multiple SAP installations (databases)?

Thanks in advance.

sks

[Turgay Cavdar]

Have you checked rsync? rsync can be used to transfer files, it also include compression option.

If you have a big environment a lot of servers/large capacities then storage based replication is more easy/managable in terms of administration. Host based replication is good when you have a small environment and you want to decrease costs (if don't want to deal with storage rep. licensing costs).

[Sanjay Kumar Suri]

Not tried rsync. But rsync is not included in 11.23/11.31.

Out environment/need is big but network link cost is killing.

sks

[Turgay Cavdar]

you can download rsync from software.hp.com which is in HP-UX Internet Express for HP-UX 11i v2.

[Sanjay Kumar Suri]

Waiting for more responses.

sks

[Duncan Edmonstone]

Presumably as this is replicated this is a critical system yes? If so you can immediately discount all the FTP/rsync like solutions - they will be bespoke, complex and completely unsupported by SAP.

Dataguard is certainly an option (as long as you are on Oracle 10g or higher - I wouldn't use the version in 9i) and will certainly use less bandwidth (as much as 5 times less), but remember that you also have to think about latency in replication technologies and that will be unchanged (in fact it may be slightly higher!) I'd also caution you that it will require some pretty strong management and governance (I hope you have good DBAs), and that _you_ will need to ensure everything in the environment that isn't in the database is kept in sync.

Do you have clusters at either end of the replication? One warining with DataGuard is that you can't use the Dataguard Broker for management if you have cold failover clusters (like Serviceguard) at either end of the replication - you can still use Dtagauard, but you have to manage everything through SQL commands rather than broker commands.

My advice would be to go through your SAP support contacts to get at SAP's own advice on using Dataguard with SAP.

HTH

Duncan