Announcement: SnowMirror 3.2 – Consistency Check
The new release SnowMirror 3.2 brings several improvements and fixes as requested by our growing user base. The most important feature is the Consistency Check which compares the number of records on both sides and raises a warning if necessary. Another feature is the log retention job improving SnowMirror operations in long-term. The release contains many other small improvements and bug fixes as well.
If enabled, SnowMirror compares the number of records in ServiceNow with the number of records in the mirror DB after each synchronization run. If there is an inconsistency in the numbers then the run finishes with a new warning status. New notification types are available so SnowMirror is able to send emails on warnings.
This feature is enabled by default when installing SnowMirror 3.2 from scratch. Users upgrading to this new version would have to enable the consistency check manually in Settings -> General Settings.
If any synchronization finishes in a warning status then the troubleshooting comes into play. The first step would be to check the activity log. There is a new section at the end of each run where SnowMirror logs messages about the consistency check. It is easy to figure out if there are records missing in the mirror DB or the other way round. See the log snapshot:
To fix the consistency issue there is the good old Clean & Synchronize command to perform a full load. Which might take some time obviously and which might cause an outage in reporting. Since 3.2 there is a new feature called Differential Synchronization. This type of synchronization compares the sys_ids on both sides and downloads the missing records and removes the orphans. The benefit is that it is significantly faster than the full load and there is no outage of the mirror table.
Please note that these features are available in the Enterprise Edition only.
Activity Log Retention
If you run SnowMirror for a long time or if the synchronization intervals are short then the amount of activity logs grows quickly. The new Activity Log Retention feature purges older logs optionally including the records in the configuration database.
This feature is enabled for all new installations. By default all the replication history including the activity logs is removed after 30 days. Upgrading users have to enable this feature manually again.
Temporary Tables for Full Loads
There is a new option which allows to perform all full loads using temporary tables. So the load is inserting a data into the temp table and the original table is available for reporting. After the load is successful the tables are swapped and the original table then removed. Enable this feature in Settings -> General Settings.
Improved Validate Button
The Validate button on the synchronization edit screen has been improved a lot. It performs more checks and the messages are more detailed. We strongly recommend running the validation before creating every single new synchronization
No More Edition-Specific Releases
SnowMirror is now distributed as a single package regardless on the edition. All the features available in the editions are driven by the license only.