This knowledgebase article provides information about an issue where if Heartbeat V4.6 cannot access protected files on the passive server, the files will be marked as 'Out-of-Sync' and may remain queued for long periods of time. If a switchover or failover occurs, data could be lost.
With Neverfail Heartbeat V4.6 installed, protected files on the passive server are marked as 'Out-of-Sync' and remain queued for long periods of time.
Under normal conditions when Heartbeat is performing replicating operations on a protected file, if Heartbeat cannot access the protected file on the passive server then it will mark the file "out-of-sync" and then resynchronize the file between the active server and the passive server. Neverfail has discovered a situation where the resynchronization operation can be queued for a long time, resulting in the potential for files to be "out-of-sync" for long periods. If the server roles are switched or if there is a failover during this period, the updates to those files queued for resynchronization could be lost. This issue only occurs with the version 4.6 of Heartbeat.
While the likelihood of the failure happening seems very small, the potential risk to the protected data is harder to estimate. In accordance with Neverfail’s policy of keeping our partners and customers informed, we are making this information public.
Note: Neverfail has released a new version (V4.6.1) that can be used for future installations.
The following work-around was available prior to the release of Neverfail Heartbeat V4.6.1.
The problem occurs in some new code that we introduced in V4.6 to optimize the operation of Heartbeat on the small minority of servers that have many (i. e. millions) of small files. The workaround is to disable that new code using the attached script and follow these steps:
- Shutdown Neverfail Heartbeat
- Download and extract UseOOSWork.zip to a suitable location.
- Run the UseOOSWork.reg script on BOTH Primary and Secondary servers. In each case: if a 'Run' button appears, click on that button; then click 'Yes' or 'OK' when asked if you want to update the registry.
- Restart Neverfail Heartbeat.
Neverfail Heartbeat V4.6