HDR Parameters and their Meaning

DRTIMEOUT

DRTIMEOUT specifies the upper limit of time that the Primary will wait for an acknowledgment from the Secondary until it assumes a data replication failure. Checkpoints on the Secondary must not exceed the DRTIMEOUT boundary. Primary and Secondary will also ping each other regardless if logical log records are send. DRTIMEOUT specifies the interval at which those pings are send. A HDR failure is assumed after four sequential ping attempts failed. So the DRTIMEOUT parameter should be set to 1/4 (25 %) of the total time that is appropriate before declaring a failure.

This parameter must have the same value on the Primary and on the Secondary.

DRINTERVAL

DRINTERVAL specifies the upper limit of seconds between flushing the data replication buffer. If HDR should run in synchronous mode, set DRINTERVAL to -1. In synchronous mode the logical-log buffer flush on the Primary completes only after the Primary server received an achknowledgment from the Secondary that the log records have been received. All settings of DRINTERVAL != -1 lead to asynchronuous mode.

This parameter must have the same value on the Primary and on the Secondary.

DRLOSTFOUND

If the Primary database server does not receive an acknowledgment inside the DRTIMEOUT timeframe, it adds the transaction information to this file (a timestamp will be added to the filename). Also during during logical recovery after a failure, the restarted Primary will place lost transaction in this file. If the file exists on the Primary, transactions have been lost. However the content of the file is binary and only useful to IBM Informix Support. You cannot reapply those transactions.

When synchronuous mode is active (DRINTERVAL -1), no entries will ever be written to the DRLOSTFOUND file.

This parameter can have different values on the Primary and on the Secondary.

DRIDXAUTO

If enabled (DRIDXAUTO 1), the Primary will autom. re-replicate an index to the Secondary if the Secondary detects a corrupt index. If an index corrupts on the Secondary and DRIDXAUTO is disabled, you have to manually replicate the index from the Primary to the Secondary using the onmode -d index ... command or you must drop and re-create the index on the Primary. DRIDXAUTO can be dynamically set using the onmode -d idxauto <on|off> command.

ENCRYPT_HDR

Starting with IDS V11 a new onconfig parameter called ENCRYPT_HDR is available. If ENCRYPT_HDR is set to 1 data transfers between the Primary and the Secondary will be encrypted. This parameter works in conjunction with other encryption parameters that are shared between HDR and ER (ENCRYPT_CIPHERS, ENCRYPT_MAC, ENCRYPT_MACFILE, ENCRYPT_SWITCH). HDR encryption and Client-/Server encrpytion must use different network ports.

This parameter must have the same value on the Primary and on the Secondary.

DRAUTO

DRAUTO controls the behaviour of the Secondary when the Primary fails. A value of 0 disables automatic switchover, the administrator must manually switch the Secondary to Standard mode (onmode -d standard) should the Primary fail. DRAUTO 1 or 2 enables automatic switchover with a different behaviour after the previous failed Primary comes online again. However you should only set DRAUTO != 0 if you have an extremly reliable network link between the Primary and the Secondary !!

This parameter must have the same value on the Primary and on the Secondary.
The following table shows the effect of different DRAUTO settings: