HDR failure handling on network disconnection

As I know that HDR is working by HDR buffer for transferring primary data to secondary data. But what if the failure of network connection occurrs intermittently and the primary physical log was backed up to tape for freeing its space, how the informix data server handles it? Will the HDR buffer expend for keeping those outstanding data?

DANNY NG wrote: > As I know that HDR is working by HDR buffer for transferring primary data to > secondary data. But what if the failure of network connection occurrs > intermittently and the primary physical log was backed up to tape for freeing > its space, how the informix data server handles it? Will the HDR buffer expend > for keeping those outstanding data? > Danny, First, you're a bit off. The physical log isn't ever backed up in the way you imply. Second it has nothing to do with HDR. IB you are thinking of the logical logs. In an HDR environment, if the secondary is down, or the primary went down and the secondary took over, when the down server comes back online, it tells the current primary what its last logical log and log position was when it crashed and the primary resends the logical log records that it missed if they are still online. This happens even if the logical logs have been backed up already and are marked free for reuse. When archived the logs are not deleted, just marked as available to be overwritten. If the required logs are no longer online, ie they have indeed been reused, then when you restart the secondary it will report 'DR: Start Failure recovery from tape'. If that happens then you have to roll forward the logs from logical log archives at least to the point where the primary can pass the remaining logical log records to the secondary (using ontape -l or onbar -l) to complete the synchronization. If it's the primary thatfailed, the recovery is similar but may not be quite as automatic. See the Administrator's Guide Chapter 20, the sections on 'Restarting If Critical Data Is Not Damaged' which is on pages 20-26ff in the IDS 11.10 manuals (pages in earlier manual versions will differ). Art S. Kagel

Is the process of logical log rolling forward by "ontape" or "onbar" are automatic?