HDR Performance

I want to know - How to measure/estimate the Network Bandwidth for a HDR pair over a WAN ? - What will happen to the performance of the Primary server if Network slows down ? - If Primary fails during high trasaction processing will the Secondary be in Sync - Are there tools/functions available in Open Admin - to monitor the trafic between the HDR pair - to see how sync the Secondary is TC

On Mar 26, 4:02 am, tc <terance.cam...@gmail.com> wrote: > I want to know > > - How to measure/estimate the Network Bandwidth for a HDR pair > over a WAN ? If this is what I think you are asking, what you would want to do is calculate the amount of data you are writing into your logical logs, which you can roughly do looking at the time it takes you to complete a logical log from the messages in the online.log and then knowing how big they are. From those two things you could get a rough amount of bytes/sec that would need to be sent from your primary machine to your secondary machine. > - What will happen to the performance of the Primary server if > Network slows down ? , If the network restricts the rate at which you can send your data to the secondary (you generate more log data then can be sent), you would start to see some bottlenecking on access to the logical logs likely (more threads waiting to access the logical log and thus slower write activity on the primary), and then also your checkpoint duration would also spike up. As the checkpoint record needs to be sent to the secondary and ack'd before it can complete on the primary and so there would be a bit of a backlog of data to be sent before the checkpoint could be sent. That backlog time would be included in the checkpoint duration. > - If Primary fails during high trasaction processing will the > Secondary > be in Sync Depends on if you use HDR in the sync or async setting. If you are using sync, then every logical log buffer flush that occurs on the primary has to be ack'd by the secondary before the log buffer flush completes on the primary. So the most that a sync HDR pair would lose is whatever was in the current logical log buffer on the primary when it crashed. If you are using async mode the logical log buffer flushes in the primary don't need to be sent and ack'd before continueing. In this case there are 12 buffers (of logical log buffer size) on the primary that are used to store logical log buffer data that could be full and waiting to be sent, so then that would be the largest amount of data your secondary server would not receive if your primary crashed with all 12 of those buffers full. Jacques > - Are there tools/functions available in Open Admin > - to monitor the trafic between the HDR pair > - to see how sync the Secondary is > > TC